18 files changed, 778 insertions, 904 deletions

diff --git a/src/dump.c b/src/bin/fspec/dump.c
index 8af7119..07a6757 100644
--- a/src/dump.c
+++ b/src/bin/fspec/dump.c
@@ -14,9 +14,12 @@
 #include <fspec/bcode.h>
 #include <fspec/lexer.h>
 #include <fspec/validator.h>
+#include "util/membuf.h"
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
 
+#if 0
+
 static size_t
 to_hex(const uint8_t *buf, const size_t buf_sz, char *out, const size_t out_sz, const bool reverse)
 {
@@ -737,6 +740,7 @@ execute(const struct fspec_mem *mem)
 
    free(context.decl);
 }
+#endif
 
 static FILE*
 fopen_or_die(const char *path, const char *mode)
@@ -754,17 +758,28 @@ fopen_or_die(const char *path, const char *mode)
 
 struct lexer {
    struct fspec_lexer lexer;
+   struct membuf output;
    FILE *file;
 };
 
 static size_t
-fspec_lexer_read(struct fspec_lexer *lexer, void *ptr, const size_t size, const size_t nmemb)
+fspec_lexer_write(struct fspec_lexer *lexer, const enum fspec_lexer_section section, const void *output, const size_t size, const size_t nmemb)
+{
+   assert(lexer && output);
+   // struct lexer *l = container_of(lexer, struct lexer, lexer);
+   (void)lexer, (void)section, (void)size, (void)nmemb;
+   return nmemb;
+}
+
+static size_t
+fspec_lexer_read(struct fspec_lexer *lexer, void *input, const size_t size, const size_t nmemb)
 {
-   assert(lexer && ptr);
+   assert(lexer && input);
    struct lexer *l = container_of(lexer, struct lexer, lexer);
-   return fread(ptr, size, nmemb, l->file);
+   return fread(input, size, nmemb, l->file);
 }
 
+#if 0
 static size_t
 fspec_validator_read(struct fspec_validator *validator, void *ptr, const size_t size, const size_t nmemb)
 {
@@ -776,6 +791,7 @@ fspec_validator_read(struct fspec_validator *validator, void *ptr, const size_t
    assert(validator->mem.input.len == 0);
    return read;
 }
+#endif
 
 int
 main(int argc, const char *argv[])
@@ -784,26 +800,28 @@ main(int argc, const char *argv[])
       errx(EXIT_FAILURE, "usage: %s file.spec < data", argv[0]);
 
    char output[4096];
-   struct fspec_mem bcode = {0};
 
    {
       char input[4096];
       struct lexer l = {
          .lexer = {
             .ops.read = fspec_lexer_read,
-            .mem.input = { .data = input, sizeof(input) },
-            .mem.output = { .data = output, sizeof(output) },
+            .ops.write = fspec_lexer_write,
+            .mem.input = { .data = input, .len = sizeof(input) },
          },
          .file = fopen_or_die(argv[1], "rb"),
+         .output.mem = { .data = output, .len = sizeof(output) },
       };
 
       if (!fspec_lexer_parse(&l.lexer, argv[1]))
          exit(EXIT_FAILURE);
 
       fclose(l.file);
-      bcode = l.lexer.mem.output;
+      // bcode = l.lexer.mem.output;
    }
 
+#if 0
+
    {
       struct fspec_validator validator = {
          .ops.read = fspec_validator_read,
@@ -815,5 +833,6 @@ main(int argc, const char *argv[])
    }
 
    execute(&bcode);
+#endif
    return EXIT_SUCCESS;
 }
diff --git a/src/fspec/bcode.c b/src/fspec/bcode.c
index 0d0d3fd..70e4b08 100644
--- a/src/fspec/bcode.c
+++ b/src/fspec/bcode.c
@@ -1,5 +1,6 @@
 #include <fspec/bcode.h>
-#include "bcode-internal.h"
+#include <fspec/memory.h>
+#include "private/bcode-types.h"
 
 #include <stdlib.h>
 #include <string.h>
@@ -8,7 +9,15 @@
 
 static_assert(sizeof(fspec_off) <= sizeof(((struct fspec_mem*)0)->len), "fspec_off should not be larger than what fspec_mem can represent");
 static_assert(sizeof(enum fspec_op) == sizeof(uint8_t), "enum fspec_op is expected to have size of uint8_t");
-static_assert(sizeof(enum fspec_arg) == sizeof(uint8_t), "enum fspec_arg is expected to have size of uint8_t");
+static_assert(sizeof(struct fspec_bcode) == sizeof(enum fspec_op), "struct fspec_bcode is expected to have size of enum fspec_op");
+static_assert(sizeof(FSPEC_OP_LAST) <= 8, "op codes need more than 3 bits to be represented");
+
+#if 0
+uint8_t
+fspec_op_get_num_args(const struct fspec_op_code *code)
+{
+   return code->op >> 2;
+}
 
 static fspec_off
 arg_data_len(const enum fspec_arg *arg)
@@ -187,3 +196,4 @@ fspec_op_next(const enum fspec_op *start, const void *end, const bool skip_args)
 
    return NULL;
 }
+#endif
diff --git a/src/fspec/bcode.h b/src/fspec/bcode.h
index d84060e..3d216af 100644
--- a/src/fspec/bcode.h
+++ b/src/fspec/bcode.h
@@ -1,7 +1,5 @@
 #pragma once
 
-#include <fspec/memory.h>
-
 #include <inttypes.h>
 #include <stdint.h>
 #include <stdbool.h>
@@ -10,34 +8,6 @@
 #define PRI_FSPEC_NUM PRIu64
 typedef uint64_t fspec_num;
 
-enum fspec_arg {
-   FSPEC_ARG_DAT,
-   FSPEC_ARG_OFF,
-   FSPEC_ARG_NUM,
-   FSPEC_ARG_VAR,
-   FSPEC_ARG_STR,
-   FSPEC_ARG_EOF,
-   FSPEC_ARG_LAST,
-} __attribute__((packed));
-
-void
-fspec_arg_get_mem(const enum fspec_arg *arg, const void *data, struct fspec_mem *out_mem);
-
-fspec_num
-fspec_arg_get_num(const enum fspec_arg *arg);
-
-const char*
-fspec_arg_get_cstr(const enum fspec_arg *arg, const void *data);
-
-const enum fspec_arg*
-fspec_arg_next(const enum fspec_arg *arg, const void *end, const uint8_t nth, const uint32_t expect);
-
-enum fspec_declaration {
-   FSPEC_DECLARATION_STRUCT,
-   FSPEC_DECLARATION_MEMBER,
-   FSPEC_DECLARATION_LAST,
-} __attribute__((packed));
-
 enum fspec_visual {
    FSPEC_VISUAL_NUL,
    FSPEC_VISUAL_DEC,
@@ -46,19 +16,77 @@ enum fspec_visual {
    FSPEC_VISUAL_LAST,
 } __attribute__((packed));
 
+enum fspec_type {
+   FSPEC_TYPE_CODE,
+   FSPEC_TYPE_CALL,
+   FSPEC_TYPE_U8,
+   FSPEC_TYPE_S8,
+   FSPEC_TYPE_U16,
+   FSPEC_TYPE_S16,
+   FSPEC_TYPE_U32,
+   FSPEC_TYPE_S32,
+   FSPEC_TYPE_U64,
+   FSPEC_TYPE_S64,
+   FSPEC_TYPE_LAST,
+} __attribute__((packed));
+
+enum fspec_storage {
+   FSPEC_STORAGE_DATA,
+   FSPEC_STORAGE_LOCAL,
+   FSPEC_STORAGE_LAST,
+} __attribute__((packed));
+
+enum fspec_builtin {
+   FSPEC_BUILTIN_ADD,
+   FSPEC_BUILTIN_SUB,
+   FSPEC_BUILTIN_MUL,
+   FSPEC_BUILTIN_DIV,
+   FSPEC_BUILTIN_MOD,
+   FSPEC_BUILTIN_BIT_AND,
+   FSPEC_BUILTIN_BIT_OR,
+   FSPEC_BUILTIN_BIT_XOR,
+   FSPEC_BUILTIN_BIT_LEFT,
+   FSPEC_BUILTIN_BIT_RIGHT,
+   FSPEC_BUILTIN_DECLARE,
+   FSPEC_BUILTIN_READ,
+   FSPEC_BUILTIN_FILTER,
+   FSPEC_BUILTIN_VISUAL,
+   FSPEC_BUILTIN_LAST,
+} __attribute__((packed));
+
 enum fspec_op {
-   FSPEC_OP_ARG,
-   FSPEC_OP_HEADER,
-   FSPEC_OP_DECLARATION,
-   FSPEC_OP_READ,
-   FSPEC_OP_GOTO,
-   FSPEC_OP_FILTER,
-   FSPEC_OP_VISUAL,
+   FSPEC_OP_BUILTIN,
+   FSPEC_OP_PUSH,
+   FSPEC_OP_POP,
+   FSPEC_OP_VAR,
    FSPEC_OP_LAST,
 } __attribute__((packed));
 
-const enum fspec_op*
-fspec_op_next(const enum fspec_op *op, const void *end, const bool skip_args);
+struct fspec_bcode {
+   char op, data[];
+} __attribute__((packed));
+
+#if 0
+('fspc')(version)
+OP_BUILTIN (declare) OP_PUSH OP_VAR8 (storage) OP_VAR8 (type) OP_VAR [name] OP_POP
+OP_BUILTIN (filter)
+OP_FUN FUN_ASSIGN VAR0 VAR [data]
+OP_FUN FUN_READ
+#endif
 
-const enum fspec_arg*
-fspec_op_get_arg(const enum fspec_op *op, const void *end, const uint8_t nth, const uint32_t expect);
+#if 0
+uint8_t
+fspec_op_get_num_args(const struct fspec_bcode *code);
+
+const struct fspec_bcode*
+fspec_op_next(const struct fspec_bcode *code, const void *end, const bool skip_args);
+
+const struct fspec_bcode*
+fspec_op_get_arg(const struct fspec_bcode *code, const void *end, const uint8_t nth, const uint32_t expect);
+
+const struct fspec_arg*
+fspec_arg_next(const struct fspec_bcode *code, const void *end, const uint8_t nth, const uint32_t expect);
+
+fspec_num
+fspec_ref_get_num(const struct fspec_bcode *code);
+#endif
diff --git a/src/fspec/lexer.h b/src/fspec/lexer.h
index 7b60e6b..ef6e059 100644
--- a/src/fspec/lexer.h
+++ b/src/fspec/lexer.h
@@ -2,14 +2,22 @@
 
 #include <fspec/memory.h>
 
+#include <stdbool.h>
+
+enum fspec_lexer_section {
+   FSPEC_SECTION_DATA,
+   FSPEC_SECTION_CODE,
+};
+
 struct fspec_lexer;
 struct fspec_lexer {
    struct {
-      size_t (*read)(struct fspec_lexer *lexer, void *ptr, const size_t size, const size_t nmemb);
+      size_t (*read)(struct fspec_lexer *lexer, void *input, const size_t size, const size_t nmemb);
+      size_t (*write)(struct fspec_lexer *lexer, const enum fspec_lexer_section section, const void *output, const size_t size, const size_t nmemb);
    } ops;
 
    struct {
-      struct fspec_mem input, output;
+      struct fspec_mem input;
    } mem;
 };
 
diff --git a/src/fspec/lexer.rl b/src/fspec/lexer.rl
deleted file mode 100644
index 51d1a54..0000000
--- a/src/fspec/lexer.rl
+++ /dev/null
@@ -1,616 +0,0 @@
-#include "ragel/ragel.h"
-#include <fspec/bcode.h>
-#include <fspec/lexer.h>
-#include "bcode-internal.h"
-
-#include <stdlib.h>
-#include <string.h>
-#include <assert.h>
-#include <err.h>
-
-#define PLACEHOLDER 0xDEADBEEF
-#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
-
-typedef uint8_t fspec_strsz;
-
-struct membuf {
-   struct fspec_mem mem;
-   fspec_off written;
-};
-
-static void
-membuf_bounds_check(const struct membuf *buf, const fspec_off nmemb)
-{
-   assert(buf);
-
-   if (buf->mem.len < nmemb || buf->written > buf->mem.len - nmemb)
-      errx(EXIT_FAILURE, "%s: %" PRI_FSPEC_OFF " bytes exceeds the maximum storage size of %zu bytes", __func__, buf->written + nmemb, buf->mem.len);
-}
-
-static void
-membuf_terminate(struct membuf *buf, const void *data, const fspec_off data_sz)
-{
-   membuf_bounds_check(buf, data_sz);
-   memcpy((char*)buf->mem.data + buf->written, data, data_sz);
-}
-
-static void
-membuf_replace(struct membuf *buf, const fspec_off off, const void *data, const fspec_off data_sz)
-{
-   assert(buf->mem.len >= data_sz && off <= buf->mem.len - data_sz);
-   memcpy((char*)buf->mem.data + off, data, data_sz);
-}
-
-static void
-membuf_append_at(struct membuf *buf, const fspec_off off, const void *data, const fspec_off data_sz)
-{
-   assert(off <= buf->written);
-   membuf_bounds_check(buf, data_sz);
-   const size_t rest = buf->written - off;
-   memmove((char*)buf->mem.data + off + data_sz, (char*)buf->mem.data + off, rest);
-   membuf_replace(buf, off, data, data_sz);
-   buf->written += data_sz;
-   assert(buf->written <= buf->mem.len);
-}
-
-static void
-membuf_append(struct membuf *buf, const void *data, const fspec_off data_sz)
-{
-   membuf_append_at(buf, buf->written, data, data_sz);
-}
-
-struct varbuf {
-   struct membuf buf;
-   fspec_off offset;
-};
-
-static inline void
-varbuf_begin(struct varbuf *var)
-{
-   assert(var);
-   var->offset = var->buf.written;
-   assert(var->offset <= var->buf.mem.len);
-}
-
-static void
-varbuf_reset(struct varbuf *var)
-{
-   assert(var);
-   var->offset = var->buf.written = 0;
-}
-
-static inline void
-varbuf_remove_last(struct varbuf *var)
-{
-   assert(var);
-   assert(var->buf.written >= var->offset);
-   const fspec_off size = var->buf.written - var->offset;
-   assert(var->buf.written >= size);
-   var->buf.written -= size;
-   assert(var->buf.written <= var->buf.mem.len);
-}
-
-enum section {
-   SECTION_DATA,
-   SECTION_CODE,
-   SECTION_LAST,
-};
-
-struct codebuf {
-   struct membuf buf;
-   const void *decl[FSPEC_DECLARATION_LAST], *end[SECTION_LAST], *strings;
-   fspec_var declarations;
-};
-
-static void
-codebuf_append(struct codebuf *code, const enum section section, const void *data, const fspec_off data_sz)
-{
-   assert(code->end[section]);
-   const fspec_off off = (char*)code->end[section] - (char*)code->buf.mem.data;
-   membuf_append_at(&code->buf, off, data, data_sz);
-
-   for (enum section s = section; s < ARRAY_SIZE(code->end); ++s) {
-      code->end[s] = (char*)code->end[s] + data_sz;
-      assert((char*)code->end[s] <= (char*)code->buf.mem.data + code->buf.mem.len);
-   }
-
-   if (section == SECTION_DATA) {
-      for (enum fspec_declaration d = 0; d < ARRAY_SIZE(code->decl); ++d) {
-         code->decl[d] = (code->decl[d] ? (char*)code->decl[d] + data_sz : NULL);
-         assert((char*)code->decl[d] <= (char*)code->buf.mem.data + code->buf.mem.len);
-      }
-   }
-
-   assert(code->end[SECTION_DATA] <= code->end[SECTION_CODE]);
-   assert((char*)code->end[SECTION_CODE] == (char*)code->buf.mem.data + code->buf.written);
-}
-
-static void
-codebuf_append_op(struct codebuf *code, const enum fspec_op op)
-{
-   codebuf_append(code, SECTION_CODE, &op, sizeof(op));
-}
-
-static uint8_t
-arg_sizeof(const enum fspec_arg type)
-{
-   switch (type) {
-      case FSPEC_ARG_DAT:
-      case FSPEC_ARG_OFF:
-      case FSPEC_ARG_STR:
-         return sizeof(fspec_off);
-
-      case FSPEC_ARG_NUM:
-         return sizeof(fspec_num);
-
-      case FSPEC_ARG_VAR:
-         return sizeof(fspec_var);
-
-      case FSPEC_ARG_EOF:
-         break;
-
-      case FSPEC_ARG_LAST:
-         errx(EXIT_FAILURE, "%s: unexpected argument type %u", __func__, type);
-   }
-
-   return 0;
-}
-
-static void
-codebuf_append_arg(struct codebuf *code, const enum fspec_arg type, const void *v)
-{
-   assert(code);
-   codebuf_append_op(code, FSPEC_OP_ARG);
-   codebuf_append(code, SECTION_CODE, &type, sizeof(type));
-   codebuf_append(code, SECTION_CODE, v, arg_sizeof(type));
-}
-
-static void
-codebuf_replace_arg(struct codebuf *code, const enum fspec_arg *arg, const enum fspec_arg type, const void *v)
-{
-   assert(code && arg);
-   assert(*arg == type);
-   const fspec_off off = ((char*)arg + 1) - (char*)code->buf.mem.data;
-   membuf_replace(&code->buf, off, v, arg_sizeof(type));
-}
-
-static bool
-get_string_offset(const void *start, const void *end, const void *str, const fspec_strsz str_sz, void const **out_off)
-{
-   assert(out_off);
-
-   while (start < end) {
-      fspec_strsz len;
-      memcpy(&len, start, sizeof(len));
-      if (len == str_sz && !memcmp((char*)start + sizeof(len), str, len)) {
-         *out_off = start;
-         return true;
-      }
-      start = (char*)start + sizeof(len) + len + 1;
-   }
-
-   return false;
-}
-
-static void
-codebuf_append_arg_cstr(struct codebuf *code, const void *str, const fspec_strsz str_sz)
-{
-   const void *ptr;
-   if (!get_string_offset(code->strings, code->end[SECTION_DATA], str, str_sz, &ptr)) {
-      ptr = code->end[SECTION_DATA];
-      codebuf_append(code, SECTION_DATA, &str_sz, sizeof(str_sz));
-      codebuf_append(code, SECTION_DATA, str, str_sz);
-      codebuf_append(code, SECTION_DATA, (char[]){ 0 }, 1);
-   }
-
-   const fspec_off off = (char*)ptr - (char*)code->buf.mem.data;
-   codebuf_append_arg(code, FSPEC_ARG_STR, &off);
-}
-
-static const enum fspec_op*
-get_named_op(const enum fspec_op *start, const void *end, const void *data, const enum fspec_op op, const uint8_t nth, const void *name, const fspec_strsz name_sz, fspec_var *out_id)
-{
-   fspec_var id = 0;
-   if ((void*)start < end && *start == FSPEC_OP_DECLARATION)
-      id = fspec_arg_get_num(fspec_op_get_arg(start, end, 2, 1<<FSPEC_ARG_NUM));
-
-   for (const enum fspec_op *p = start; p; p = fspec_op_next(p, end, true)) {
-      const enum fspec_arg *arg;
-      if (*p != op || !(arg = fspec_op_get_arg(p, end, nth, 1<<FSPEC_ARG_STR)))
-         continue;
-
-      struct fspec_mem str;
-      fspec_arg_get_mem(arg, data, &str);
-      if (str.len == name_sz && !memcmp(name, str.data, name_sz)) {
-         if (out_id)
-            *out_id = id;
-
-         return p;
-      }
-
-      ++id;
-   }
-
-   return NULL;
-}
-
-static const enum fspec_op*
-get_declaration(struct codebuf *code, const bool member, const struct fspec_mem *str, fspec_var *out_id)
-{
-   const void *start = (member ? code->decl[FSPEC_DECLARATION_STRUCT] : code->end[SECTION_DATA]);
-   return get_named_op(start, code->end[SECTION_CODE], code->buf.mem.data, FSPEC_OP_DECLARATION, 4, str->data, str->len, out_id);
-}
-
-static bool
-codebuf_append_arg_var(struct codebuf *code, const bool member, const struct fspec_mem *var)
-{
-   fspec_var id = -1;
-   if (!get_declaration(code, member, var, &id))
-      return false;
-
-   codebuf_append_arg(code, FSPEC_ARG_VAR, &id);
-   return true;
-}
-
-static void
-codebuf_append_declaration(struct codebuf *code, const enum fspec_declaration decl)
-{
-   code->decl[decl] = code->end[SECTION_CODE];
-   codebuf_append_op(code, FSPEC_OP_DECLARATION);
-   codebuf_append_arg(code, FSPEC_ARG_NUM, (fspec_num[]){ decl });
-   codebuf_append_arg(code, FSPEC_ARG_NUM, (fspec_num[]){ code->declarations++ });
-   codebuf_append_arg(code, FSPEC_ARG_OFF, (fspec_off[]){ PLACEHOLDER });
-}
-
-enum stack_type {
-   STACK_STR,
-   STACK_NUM,
-};
-
-struct stack {
-   union {
-      struct fspec_mem str;
-      uint64_t num;
-   };
-   enum stack_type type;
-};
-
-static const char*
-stack_type_to_str(const enum stack_type type)
-{
-   switch (type) {
-      case STACK_STR: return "str";
-      case STACK_NUM: return "num";
-   };
-   return "unknown";
-}
-
-static void
-stack_check_type(const struct stack *stack, const enum stack_type type)
-{
-   assert(stack);
-
-   if (stack->type != type)
-      errx(EXIT_FAILURE, "tried to get '%s' from stack, but the last pushed type was '%s'", stack_type_to_str(type), stack_type_to_str(stack->type));
-}
-
-static const struct fspec_mem*
-stack_get_str(const struct stack *stack)
-{
-   stack_check_type(stack, STACK_STR);
-   return &stack->str;
-}
-
-static uint64_t
-stack_get_num(const struct stack *stack)
-{
-   stack_check_type(stack, STACK_NUM);
-   return stack->num;
-}
-
-struct state {
-   struct ragel ragel;
-   struct stack stack;
-   struct codebuf out;
-   struct varbuf var;
-};
-
-static void
-state_stack_num(struct state *state, const uint8_t base)
-{
-   assert(state);
-   membuf_terminate(&state->var.buf, (char[]){ 0 }, 1);
-   const char *str = (char*)state->var.buf.mem.data + state->var.offset;
-   state->stack.type = STACK_NUM;
-   state->stack.num = strtoll(str + (base == 16 && *str == 'x'), NULL, base);
-   varbuf_remove_last(&state->var);
-}
-
-static void
-state_append_arg_var(struct state *state, const bool member, const struct fspec_mem *str)
-{
-   assert(state && str);
-
-   if (!codebuf_append_arg_var(&state->out, member, str))
-      ragel_throw_error(&state->ragel, "'%s' undeclared", (char*)str->data);
-}
-
-static void
-state_append_declaration(struct state *state, const enum fspec_declaration decl, const struct fspec_mem *str)
-{
-   assert(state && str);
-
-   if (get_declaration(&state->out, (decl == FSPEC_DECLARATION_MEMBER), str, NULL))
-      ragel_throw_error(&state->ragel, "'%s' redeclared", (char*)str->data);
-
-   codebuf_append_declaration(&state->out, decl);
-   codebuf_append_arg_cstr(&state->out, str->data, str->len);
-}
-
-static void
-state_finish_declaration(struct state *state, const enum fspec_declaration decl)
-{
-   assert(state && state->out.decl[decl]);
-   const char *end = state->out.end[SECTION_CODE];
-   const fspec_off off = end - (char*)state->out.decl[decl];
-   codebuf_replace_arg(&state->out, fspec_op_get_arg(state->out.decl[decl], end, 3, 1<<FSPEC_ARG_OFF), FSPEC_ARG_OFF, &off);
-   state->out.decl[decl] = NULL;
-}
-
-%%{
-   machine fspec_lexer;
-   variable p state.ragel.p;
-   variable pe state.ragel.pe;
-   variable eof state.ragel.eof;
-   write data noerror nofinal;
-
-   action arg_eof {
-      codebuf_append_arg(&state.out, FSPEC_ARG_EOF, NULL);
-   }
-
-   action arg_num {
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ stack_get_num(&state.stack) });
-   }
-
-   action arg_str {
-      const struct fspec_mem *str = stack_get_str(&state.stack);
-      codebuf_append_arg_cstr(&state.out, str->data, str->len);
-   }
-
-   action arg_var {
-      state_append_arg_var(&state, true, stack_get_str(&state.stack));
-   }
-
-   action filter {
-      codebuf_append_op(&state.out, FSPEC_OP_FILTER);
-   }
-
-   action goto {
-      codebuf_append_op(&state.out, FSPEC_OP_GOTO);
-      state_append_arg_var(&state, false, stack_get_str(&state.stack));
-   }
-
-   action vnul {
-      codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_NUL });
-   }
-
-   action vdec {
-      codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_DEC });
-   }
-
-   action vhex {
-      codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_HEX });
-   }
-
-   action vstr {
-      codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_STR });
-   }
-
-   action r8 {
-      codebuf_append_op(&state.out, FSPEC_OP_READ);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 8 });
-   }
-
-   action r16 {
-      codebuf_append_op(&state.out, FSPEC_OP_READ);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 16 });
-   }
-
-   action r32 {
-      codebuf_append_op(&state.out, FSPEC_OP_READ);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 32 });
-   }
-
-   action r64 {
-      codebuf_append_op(&state.out, FSPEC_OP_READ);
-      codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 64 });
-   }
-
-   action member_end {
-      state_finish_declaration(&state, FSPEC_DECLARATION_MEMBER);
-   }
-
-   action member_start {
-      state_append_declaration(&state, FSPEC_DECLARATION_MEMBER, stack_get_str(&state.stack));
-   }
-
-   action struct_end {
-      state_finish_declaration(&state, FSPEC_DECLARATION_STRUCT);
-   }
-
-   action struct_start {
-      state_append_declaration(&state, FSPEC_DECLARATION_STRUCT, stack_get_str(&state.stack));
-   }
-
-   action stack_oct {
-      state_stack_num(&state, 8);
-   }
-
-   action stack_hex {
-      state_stack_num(&state, 16);
-   }
-
-   action stack_dec {
-      state_stack_num(&state, 10);
-   }
-
-   action stack_str {
-      membuf_terminate(&state.var.buf, (char[]){ 0 }, 1);
-      state.stack.type = STACK_STR;
-      state.stack.str = state.var.buf.mem;
-      state.stack.str.len = state.var.buf.written;
-   }
-
-   action store_esc_num {
-      const fspec_num v = stack_get_num(&state.stack);
-      assert(v <= 255);
-      const uint8_t u8 = v;
-      membuf_append(&state.var.buf, &u8, sizeof(u8));
-   }
-
-   action store_esc {
-      const struct { const char e, v; } map[] = {
-         { .e = 'a', .v = '\a' },
-         { .e = 'b', .v = '\b' },
-         { .e = 'f', .v = '\f' },
-         { .e = 'n', .v = '\n' },
-         { .e = 'r', .v = '\r' },
-         { .e = 't', .v = '\t' },
-         { .e = 'v', .v = '\v' },
-         { .e = '\\', .v = '\\' },
-         { .e = '\'', .v = '\'' },
-         { .e = '\"', .v = '"' },
-         { .e = 'e', .v = 0x1B },
-      };
-
-      for (size_t i = 0; i < ARRAY_SIZE(map); ++i) {
-         if (*state.ragel.p != map[i].e)
-            continue;
-
-         membuf_append(&state.var.buf, &map[i].v, sizeof(map[i].v));
-         break;
-      }
-   }
-
-   action store {
-      membuf_append(&state.var.buf, state.ragel.p, 1);
-   }
-
-   action begin_num {
-      varbuf_begin(&state.var);
-   }
-
-   action begin_str {
-      varbuf_reset(&state.var);
-   }
-
-   action type_err {
-      ragel_throw_error(&state.ragel, "unknown type name");
-   }
-
-   action visual_err {
-      ragel_throw_error(&state.ragel, "unknown visualization");
-   }
-
-   action syntax_err {
-      ragel_throw_error(&state.ragel, "malformed input (machine failed here or in next expression)");
-   }
-
-   action line {
-      ragel_advance_line(&state.ragel);
-   }
-
-   # Semantic
-   quote = ['"];
-   newline = '\n';
-   esc = [abfnrtv\\'"e];
-   esc_chr = '\\';
-   esc_hex = 'x' <: xdigit{2};
-   hex = '0x' <: xdigit{1,};
-   oct = [0-7]{1,3};
-   dec = [\-+]? <: (([1-9] <: digit*) | '0');
-   valid = ^cntrl;
-   comment = '//' <: valid* :>> newline;
-   type = ('u8' | 's8') %r8 | ('u16' | 's16') %r16 | ('u32' | 's32') %r32 | ('u64' | 's64') %r64;
-   visual = 'nul' %vnul | 'dec' %vdec | 'hex' %vhex | 'str' %vstr;
-   reserved = 'struct' | type | visual;
-   name = ((alpha | '_') <: (alnum | '_')*) - reserved;
-
-   # Stack
-   stack_name = name >begin_str $store %stack_str;
-   stack_hex = hex >begin_num $store %stack_hex;
-   stack_dec = dec >begin_num $store %stack_dec;
-   stack_oct = oct >begin_num $store %stack_oct;
-   stack_esc_hex = esc_hex >begin_num $store %stack_hex;
-   stack_esc = esc_chr <: ((stack_esc_hex | stack_oct) %store_esc_num | esc %~store_esc);
-   stack_str = quote <: ((stack_esc? <: print? $store) - zlen)* >begin_str %stack_str :>> quote;
-   stack_num = stack_dec | stack_hex;
-
-   # Catchers
-   catch_struct = 'struct ' <: stack_name;
-   catch_type = (catch_struct %goto | type) $!type_err;
-   catch_args = stack_num %arg_num | stack_str %arg_str | stack_name %arg_var;
-   catch_array = '[' <: (catch_args | '$' %arg_eof) :>> ']';
-   catch_filter = ' | ' %filter <: stack_name %arg_str :>> ('(' <: catch_args? <: (', ' <: catch_args)* :>> ')')?;
-   catch_visual = ' ' <: visual $!visual_err;
-
-   # Abstract
-   member = stack_name %member_start :> ': ' <: (catch_type <: catch_array* catch_filter* catch_visual?) :>> ';' %member_end;
-   struct = catch_struct %struct_start :>> ' {' <: (space | comment | member)* :>> '};' %struct_end;
-   line = valid* :>> newline %line;
-   main := ((space | comment | struct)* & line*) $!syntax_err;
-}%%
-
-bool
-fspec_lexer_parse(struct fspec_lexer *lexer, const char *name)
-{
-   int cs;
-   %% write init;
-
-   (void)fspec_lexer_en_main;
-   assert(lexer);
-   assert(lexer->ops.read);
-   assert(lexer->mem.input.data && lexer->mem.input.len);
-   assert(lexer->mem.output.data && lexer->mem.output.len);
-   assert(lexer->mem.input.len <= (size_t)~0 && "input storage size exceeds size_t range");
-   assert(lexer->mem.output.len <= (fspec_off)~0 && "output storage size exceeds fspec_off range");
-
-   char var[256];
-   struct state state = {
-      .ragel.name = name,
-      .ragel.lineno = 1,
-      .var.buf.mem = { .data = var, .len = sizeof(var) },
-      .out.buf.mem = lexer->mem.output,
-   };
-
-   static const fspec_num version = 0;
-   state.out.end[SECTION_CODE] = state.out.end[SECTION_DATA] = state.out.buf.mem.data;
-   codebuf_append_op(&state.out, FSPEC_OP_HEADER);
-   codebuf_append_arg(&state.out, FSPEC_ARG_NUM, &version);
-   codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ PLACEHOLDER });
-   codebuf_append_arg(&state.out, FSPEC_ARG_DAT, (fspec_off[]){ PLACEHOLDER });
-   state.out.end[SECTION_DATA] = state.out.end[SECTION_CODE];
-   state.out.strings = state.out.end[SECTION_DATA];
-
-   struct fspec_mem input = lexer->mem.input;
-   for (bool eof = false; !state.ragel.error && !eof;) {
-      const size_t bytes = lexer->ops.read(lexer, input.data, 1, input.len);
-      const struct ragel_mem rl = { .data = input.data, .end = (char*)input.data + bytes };
-      ragel_feed_input(&state.ragel, (eof = (bytes < input.len)), &rl);
-      %% write exec;
-   }
-
-   {
-      const void *end = state.out.end[SECTION_CODE];
-      codebuf_replace_arg(&state.out, fspec_op_get_arg(state.out.buf.mem.data, end, 2, 1<<FSPEC_ARG_NUM), FSPEC_ARG_NUM, (fspec_num[]){ state.out.declarations });
-      const fspec_off off = (char*)state.out.end[SECTION_DATA] - (char*)state.out.strings;
-      codebuf_replace_arg(&state.out, fspec_op_get_arg(state.out.buf.mem.data, end, 3, 1<<FSPEC_ARG_DAT), FSPEC_ARG_DAT, &off);
-   }
-
-   lexer->mem.output.len = state.out.buf.written;
-   return !state.ragel.error;
-}
diff --git a/src/fspec/bcode-internal.h b/src/fspec/private/bcode-types.h
index 8c9ce74..8c9ce74 100644
--- a/src/fspec/bcode-internal.h
+++ b/src/fspec/private/bcode-types.h
diff --git a/src/fspec/ragel/lexer-expr.h b/src/fspec/ragel/lexer-expr.h
new file mode 100644
index 0000000..904736d
--- /dev/null
+++ b/src/fspec/ragel/lexer-expr.h
@@ -0,0 +1,20 @@
+#pragma once
+
+#include <fspec/memory.h>
+
+#include <stdbool.h>
+
+struct fspec_expr;
+struct fspec_expr {
+   struct {
+      size_t (*read)(struct fspec_expr *lexer, void *input, const size_t size, const size_t nmemb);
+      size_t (*write)(struct fspec_expr *lexer, const void *output, const size_t size, const size_t nmemb);
+   } ops;
+
+   struct {
+      struct fspec_mem input;
+   } mem;
+};
+
+bool
+fspec_expr_parse(struct fspec_expr *lexer, const char *name);
diff --git a/src/fspec/ragel/lexer-expr.rl b/src/fspec/ragel/lexer-expr.rl
new file mode 100644
index 0000000..2975043
--- /dev/null
+++ b/src/fspec/ragel/lexer-expr.rl
@@ -0,0 +1,122 @@
+#include "lexer-expr.h"
+#include "lexer-stack.h"
+#include "util/ragel/ragel.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <assert.h>
+#include <err.h>
+
+static uint8_t
+precedence(char op)
+{
+   switch (op) {
+      case '^': return 4;
+      case '*': return 3;
+      case '/': return 3;
+      case '+': return 2;
+      case '-': return 2;
+   }
+   errx(EXIT_FAILURE, "unknown operator %c for precedence", op);
+   return 0;
+}
+
+static size_t
+pop(char cur, char *mstack, size_t open)
+{
+   static char cvar = 'a';
+
+   // 1 + 2 + 4 + 3 * 2 / 2 * 2 * 2 - 2 * 2 + 5;
+   while (open >= 3) {
+      const char last_op = mstack[open - 2];
+      const uint8_t last_prio = precedence(last_op);
+      const uint8_t new_prio = precedence(cur);
+
+      if (last_prio <= new_prio)
+         break;
+
+      printf("%c = ", cvar);
+      for (size_t i = open - 3; i < open; ++i)
+         printf("%c ", mstack[i]);
+      puts(";");
+      open -= 3;
+
+      mstack[open++] = cvar;
+      ++cvar;
+   }
+
+   return open;
+}
+
+%%{
+   machine fspec_expr;
+   include fspec_stack "lexer-stack.rl";
+   variable p ragel.p;
+   variable pe ragel.pe;
+   variable eof ragel.eof;
+   write data noerror nofinal;
+
+   action op {
+      open = pop(fc, mstack, open);
+      mstack[open++] = fc;
+   }
+
+   logical_operators = '&&' | '||' | '==' | '<' | '>' | '<=' | '>=';
+   calc_operators = '-' | '+' | '/' | '*' | '%';
+   bitwise_operators = '&' | '|' | '^' | '<<' | '>>';
+
+   main := |*
+      '+' => op;
+      '/' => op;
+      '*' => op;
+      '-' => op;
+      '^' => op;
+      stack_num => { mstack[open++] = fc;};
+      '(' => { };
+      ')' => { };
+      ' ';
+      ';' => {
+         printf("v = ");
+         for (size_t i = 0; i < open; ++i)
+            printf("%c ", mstack[i]);
+         puts(";");
+      };
+      *|;
+}%%
+
+
+bool
+fspec_expr_parse(struct fspec_expr *expr, const char *name)
+{
+   int cs, act;
+   const char *ts, *te;
+   (void)ts;
+
+   size_t open = 0;
+   char mstack[25];
+
+   %% write init;
+
+   (void)fspec_expr_en_main;
+   assert(expr);
+   assert(expr->ops.read);
+   assert(expr->ops.write);
+   assert(expr->mem.input.data && expr->mem.input.len);
+   assert(expr->mem.input.len <= (size_t)~0 && "input storage size exceeds size_t range");
+
+   char var[256];
+   struct stack stack = { .var.buf.mem = { .data = var, .len = sizeof(var) } };
+   struct ragel ragel = { .name = name, .lineno = 1 };
+
+   // static const fspec_num version = 0;
+
+   struct fspec_mem input = expr->mem.input;
+   for (bool eof = false; !ragel.error && !eof;) {
+      const size_t bytes = expr->ops.read(expr, input.data, 1, input.len);
+      const struct ragel_mem rl = { .data = input.data, .end = (char*)input.data + bytes };
+      ragel_feed_input(&ragel, (eof = (bytes < input.len)), &rl);
+      %% write exec;
+   }
+
+   return !ragel.error;
+}
diff --git a/src/fspec/ragel/lexer-stack.h b/src/fspec/ragel/lexer-stack.h
new file mode 100644
index 0000000..eebf055
--- /dev/null
+++ b/src/fspec/ragel/lexer-stack.h
@@ -0,0 +1,42 @@
+#pragma once
+
+#include "util/membuf.h"
+
+#include <stdint.h>
+
+struct varbuf {
+   struct membuf buf;
+   size_t offset;
+};
+
+void
+varbuf_begin(struct varbuf *var);
+
+void
+varbuf_reset(struct varbuf *var);
+
+void
+varbuf_remove_last(struct varbuf *var);
+
+struct stack {
+   struct varbuf var;
+
+   union {
+      struct fspec_mem str;
+      uint64_t num;
+   };
+
+   enum stack_type {
+      STACK_STR,
+      STACK_NUM,
+   } type;
+};
+
+void
+stack_num(struct stack *stack, const uint8_t base);
+
+const struct fspec_mem*
+stack_get_str(const struct stack *stack);
+
+uint64_t
+stack_get_num(const struct stack *stack);
diff --git a/src/fspec/ragel/lexer-stack.rl b/src/fspec/ragel/lexer-stack.rl
new file mode 100644
index 0000000..940f820
--- /dev/null
+++ b/src/fspec/ragel/lexer-stack.rl
@@ -0,0 +1,153 @@
+#include "lexer-stack.h"
+
+#include <stdlib.h>
+#include <assert.h>
+#include <err.h>
+
+void
+varbuf_begin(struct varbuf *var)
+{
+   assert(var);
+   var->offset = var->buf.written;
+   assert(var->offset <= var->buf.mem.len);
+}
+
+void
+varbuf_reset(struct varbuf *var)
+{
+   assert(var);
+   var->offset = var->buf.written = 0;
+}
+
+void
+varbuf_remove_last(struct varbuf *var)
+{
+   assert(var);
+   assert(var->buf.written >= var->offset);
+   const size_t size = var->buf.written - var->offset;
+   assert(var->buf.written >= size);
+   var->buf.written -= size;
+   assert(var->buf.written <= var->buf.mem.len);
+}
+
+static void
+stack_check_type(const struct stack *stack, const enum stack_type type)
+{
+   assert(stack);
+
+   if (stack->type == type)
+      return;
+
+   const char *got = (type == STACK_STR ? "str" : "num"), *expected = (stack->type == STACK_STR ? "str" : "num");
+   errx(EXIT_FAILURE, "tried to get '%s' from stack, but the last pushed type was '%s'", got, expected);
+}
+
+void
+stack_num(struct stack *stack, const uint8_t base)
+{
+   assert(stack);
+   membuf_terminate(&stack->var.buf, (char[]){ 0 }, 1);
+   const char *str = (char*)stack->var.buf.mem.data + stack->var.offset;
+   stack->type = STACK_NUM;
+   stack->num = strtoll(str, NULL, base);
+   varbuf_remove_last(&stack->var);
+}
+
+const struct fspec_mem*
+stack_get_str(const struct stack *stack)
+{
+   stack_check_type(stack, STACK_STR);
+   return &stack->str;
+}
+
+uint64_t
+stack_get_num(const struct stack *stack)
+{
+   stack_check_type(stack, STACK_NUM);
+   return stack->num;
+}
+
+%%{
+   machine fspec_stack;
+
+   action stack_oct {
+      stack_num(&stack, 8);
+   }
+
+   action stack_hex {
+      stack_num(&stack, 16);
+   }
+
+   action stack_dec {
+      stack_num(&stack, 10);
+   }
+
+   action stack_str {
+      membuf_terminate(&stack.var.buf, (char[]){ 0 }, 1);
+      stack.type = STACK_STR;
+      stack.str = stack.var.buf.mem;
+      stack.str.len = stack.var.buf.written;
+   }
+
+   action store_esc_num {
+      const fspec_num v = stack_get_num(&stack);
+      assert(v <= 255);
+      membuf_append(&stack.var.buf, (uint8_t[]){ v }, sizeof(uint8_t));
+   }
+
+   action store_esc {
+      const struct { const char e, v; } map[] = {
+         { .e = 'a', .v = '\a' },
+         { .e = 'b', .v = '\b' },
+         { .e = 'f', .v = '\f' },
+         { .e = 'n', .v = '\n' },
+         { .e = 'r', .v = '\r' },
+         { .e = 't', .v = '\t' },
+         { .e = 'v', .v = '\v' },
+         { .e = '\\', .v = '\\' },
+         { .e = '\'', .v = '\'' },
+         { .e = '\"', .v = '"' },
+         { .e = 'e', .v = 0x1B },
+      };
+
+      for (size_t i = 0; i < sizeof(map) / sizeof(map[0]); ++i) {
+         if (fc != map[i].e)
+            continue;
+
+         membuf_append(&stack.var.buf, &map[i].v, sizeof(map[i].v));
+         break;
+      }
+   }
+
+   action store {
+      membuf_append(&stack.var.buf, fpc, 1);
+   }
+
+   action begin_num {
+      varbuf_begin(&stack.var);
+   }
+
+   action begin_str {
+      varbuf_reset(&stack.var);
+   }
+
+   # Semantic
+   quote = ['"];
+   esc = [abfnrtv\\'"e];
+   esc_chr = '\\';
+   esc_hex = 'x' <: xdigit{2};
+   hex = '0x' <: xdigit{1,};
+   oct = [0-7]{1,3};
+   dec = [\-+]? <: (([1-9] <: digit*) | '0');
+   name = ((alpha | '_') <: (alnum | '_')*);
+
+   # Stack
+   stack_name = name >begin_str $store %stack_str;
+   stack_hex = hex >begin_num $store %stack_hex;
+   stack_dec = dec >begin_num $store %stack_dec;
+   stack_oct = oct >begin_num $store %stack_oct;
+   stack_esc_hex = esc_hex >begin_num <>*store %stack_hex;
+   stack_esc = esc_chr <: ((stack_esc_hex | stack_oct) %store_esc_num | esc %~store_esc);
+   stack_str = quote <: ((stack_esc? <: print? $store) - zlen)* >begin_str %stack_str :>> quote;
+   stack_num = stack_dec | stack_hex;
+}%%
diff --git a/src/fspec/ragel/lexer.rl b/src/fspec/ragel/lexer.rl
new file mode 100644
index 0000000..b4a21dc
--- /dev/null
+++ b/src/fspec/ragel/lexer.rl
@@ -0,0 +1,180 @@
+#include <fspec/lexer.h>
+#include <fspec/bcode.h>
+#include "lexer-stack.h"
+#include "util/ragel/ragel.h"
+#include "fspec/private/bcode-types.h"
+
+#include <assert.h>
+
+%%{
+   machine fspec_lexer;
+   include fspec_stack "lexer-stack.rl";
+   variable p ragel.p;
+   variable pe ragel.pe;
+   variable eof ragel.eof;
+   write data noerror nofinal;
+
+   action arg_eof {
+      // codebuf_append_arg(&state.out, FSPEC_ARG_EOF, NULL);
+   }
+
+   action arg_num {
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ stack_get_num(&state.stack) });
+   }
+
+   action arg_str {
+      // const struct fspec_mem *str = stack_get_str(&state.stack);
+      // codebuf_append_arg_cstr(&state.out, str->data, str->len);
+   }
+
+   action arg_var {
+      // state_append_arg_var(&state, true, stack_get_str(&state.stack));
+   }
+
+   action filter {
+      // codebuf_append_op(&state.out, FSPEC_OP_FILTER);
+   }
+
+   action goto {
+      // codebuf_append_op(&state.out, FSPEC_OP_GOTO);
+      // state_append_arg_var(&state, false, stack_get_str(&state.stack));
+   }
+
+   action vnul {
+      // codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_NUL });
+   }
+
+   action vdec {
+      // codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_DEC });
+   }
+
+   action vhex {
+      // codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_HEX });
+   }
+
+   action vstr {
+      // codebuf_append_op(&state.out, FSPEC_OP_VISUAL);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ FSPEC_VISUAL_STR });
+   }
+
+   action r8 {
+      // codebuf_append_op(&state.out, FSPEC_OP_READ);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 8 });
+   }
+
+   action r16 {
+      // codebuf_append_op(&state.out, FSPEC_OP_READ);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 16 });
+   }
+
+   action r32 {
+      // codebuf_append_op(&state.out, FSPEC_OP_READ);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 32 });
+   }
+
+   action r64 {
+      // codebuf_append_op(&state.out, FSPEC_OP_READ);
+      // codebuf_append_arg(&state.out, FSPEC_ARG_NUM, (fspec_num[]){ 64 });
+   }
+
+   action enum_member_end {
+   }
+
+   action enum_member_start {
+   }
+
+   action enum_end {
+   }
+
+   action enum_start {
+   }
+
+   action struct_member_end {
+      // state_finish_declaration(&state, FSPEC_DECLARATION_MEMBER);
+   }
+
+   action struct_member_start {
+      // state_append_declaration(&state, FSPEC_DECLARATION_MEMBER, stack_get_str(&state.stack));
+   }
+
+   action struct_end {
+      // state_finish_declaration(&state, FSPEC_DECLARATION_STRUCT);
+   }
+
+   action struct_start {
+      // state_append_declaration(&state, FSPEC_DECLARATION_STRUCT, stack_get_str(&state.stack));
+   }
+
+   action type_err {
+      ragel_throw_error(&ragel, "unknown type name");
+   }
+
+   action visual_err {
+      ragel_throw_error(&ragel, "unknown visualization");
+   }
+
+   action syntax_err {
+      ragel_throw_error(&ragel, "malformed input (machine failed here or in next expression)");
+   }
+
+   action line {
+      ragel_advance_line(&ragel);
+   }
+
+   # Semantic
+   newline = '\n';
+   valid = ^cntrl;
+   comment = '//' <: valid* :>> newline;
+   type = ('u8' | 's8') %r8 | ('u16' | 's16') %r16 | ('u32' | 's32') %r32 | ('u64' | 's32') %r64;
+   visual = 'nul' %vnul | 'dec' %vdec | 'hex' %vhex | 'str' %vstr;
+
+   # Catchers
+   catch_const_expr = stack_num %arg_num;
+   catch_struct = 'struct ' <: stack_name;
+   catch_enum = 'enum ' <: stack_name;
+   catch_type = (catch_struct %goto | type) $!type_err;
+   catch_args = stack_num %arg_num | stack_str %arg_str | stack_name %arg_var;
+   catch_array = '[' <: (catch_args | '$' %arg_eof) :>> ']';
+   catch_filter = ' | ' %filter <: stack_name %arg_str :>> ('(' <: catch_args? <: (', ' <: catch_args)* :>> ')')?;
+   catch_visual = ' ' <: visual $!visual_err;
+
+   # Abstract
+   struct_member = stack_name %struct_member_start :>> ': ' <: (catch_type <: catch_array* catch_filter* catch_visual?) :>> ';' %struct_member_end;
+   struct = catch_struct %struct_start :>> ' {' <: (space | comment | struct_member)* :>> '};' %struct_end;
+   enum_member = stack_name %enum_member_start :>> (': ' <: catch_const_expr)? :>> ';' %enum_member_end;
+   enum = catch_enum %enum_start :>> ' {' <: (space | comment | enum_member)* :>> '};' %enum_end;
+   line = valid* :>> newline %line;
+   main := ((space | comment | enum | struct)* & line*) $!syntax_err;
+}%%
+
+bool
+fspec_lexer_parse(struct fspec_lexer *lexer, const char *name)
+{
+   int cs;
+   %% write init;
+
+   (void)fspec_lexer_en_main;
+   assert(lexer);
+   assert(lexer->ops.read);
+   assert(lexer->mem.input.data && lexer->mem.input.len);
+   assert(lexer->mem.input.len <= (size_t)~0 && "input storage size exceeds size_t range");
+
+   char var[256];
+   struct stack stack = { .var.buf.mem = { .data = var, .len = sizeof(var) } };
+   struct ragel ragel = { .name = name, .lineno = 1 };
+
+   // static const fspec_num version = 0;
+
+   struct fspec_mem input = lexer->mem.input;
+   for (bool eof = false; !ragel.error && !eof;) {
+      const size_t bytes = lexer->ops.read(lexer, input.data, 1, input.len);
+      const struct ragel_mem rl = { .data = input.data, .end = (char*)input.data + bytes };
+      ragel_feed_input(&ragel, (eof = (bytes < input.len)), &rl);
+      %% write exec;
+   }
+
+   return !ragel.error;
+}
diff --git a/src/fspec/ragel/validator.rl b/src/fspec/ragel/validator.rl
new file mode 100644
index 0000000..90ead21
--- /dev/null
+++ b/src/fspec/ragel/validator.rl
@@ -0,0 +1,96 @@
+#include <fspec/bcode.h>
+#include <fspec/validator.h>
+#include "util/ragel/ragel.h"
+#include "fspec/private/bcode-types.h"
+
+#include <assert.h>
+
+struct stack {
+   union {
+      fspec_num num;
+      fspec_off off;
+      fspec_var var;
+      fspec_strsz strsz;
+      unsigned char b[sizeof(fspec_num)];
+   } u;
+   uint8_t i; // writing index for u.b
+};
+
+struct state {
+   struct ragel ragel;
+   struct stack stack;
+};
+
+%%{
+   machine fspec_validator;
+   variable p state.ragel.p;
+   variable pe state.ragel.pe;
+   variable eof state.ragel.eof;
+   write data noerror nofinal;
+
+#   BLT_HEADER = 0;
+#   BLT_ADD = 1;
+#   BLT_SUB = 2;
+#   BLT_MUL = 3;
+#   BLT_DIV = 4;
+#   BLT_MOD = 5;
+#   BLT_BIT_AND = 6;
+#   BLT_BIT_OR = 7;
+#   BLT_BIT_XOR = 8;
+#   BLT_BIT_LEFT = 9;
+#   BLT_BIT_RIGHT = 10;
+#   BLT_DECLARE = 11;
+#   BLT_READ = 12;
+#   BLT_GOTO = 13;
+#   BLT_FILTER = 14;
+#   BLT_VISUAL = 15;
+#
+#   builtins = BLT_HEADER |
+#              BLT_ADD | BLT_SUB | BLT_MUL | BLT_DIV | BLT_MOD |
+#              BLT_BIT_AND | BLT_BIT_OR | BLT_BIT_XOR | BLT_BIT_LEFT | BLT_BIT_RIGHT
+#              BLT_DECLARE | BLT_READ | BLT_GOTO | BLT_FILTER | BLT_VISUAL;
+#
+#   OP_ARG = 0;
+#   OP_REF = 1;
+#   OP_BLT = 2 OP_ARG builtins;
+#   OP_FUN = 3;
+#
+#   arg_ops = OP_REF | OP_FUN | OP_BUILTIN OP_FUN
+#
+#   BLT_DECLARE = OP_BUILTIN 10 OP_ARG 2 OP_REF OP_REF;
+#   BLT_READ = OP_BUILTIN 11 OP_ARG 1..255 OP_REF (arg_ops)*;
+#
+#   pattern = ((BLT_READ | BLT_GOTO) BLT_FILTER* BLT_VISUAL?)* $!pattern_error;
+#   main := (BLT_HEADER <: BLT_DECLARE* <: pattern) %check_decls $advance $!syntax_error;
+   main := any*;
+}%%
+
+bool
+fspec_validator_parse(struct fspec_validator *validator, const char *name)
+{
+   int cs;
+   %% write init;
+
+   (void)fspec_validator_en_main;
+   assert(validator);
+   assert(validator->ops.read);
+   assert(validator->mem.input.data && validator->mem.input.len);
+   assert(validator->mem.input.len <= (size_t)~0 && "input storage size exceeds size_t range");
+
+   struct state state = {
+      .ragel.name = name,
+      .ragel.lineno = 1,
+   };
+
+   static_assert(sizeof(state.stack.u) == sizeof(state.stack.u.b), "bytes doesn't represent the largest member in union");
+
+   struct fspec_mem input = validator->mem.input;
+   for (bool eof = false; !state.ragel.error && !eof;) {
+      const size_t bytes = validator->ops.read(validator, input.data, 1, input.len);
+      const struct ragel_mem rl = { .data = input.data, .end = (char*)input.data + bytes, .binary = true };
+      ragel_feed_input(&state.ragel, (eof = (bytes < input.len)), &rl);
+      %% write exec;
+   }
+
+   return !state.ragel.error;
+}
diff --git a/src/fspec/validator.h b/src/fspec/validator.h
index c4705b2..a20e98a 100644
--- a/src/fspec/validator.h
+++ b/src/fspec/validator.h
@@ -2,6 +2,8 @@
 
 #include <fspec/memory.h>
 
+#include <stdbool.h>
+
 struct fspec_validator;
 struct fspec_validator {
    struct {
diff --git a/src/fspec/validator.rl b/src/fspec/validator.rl
deleted file mode 100644
index b00a827..0000000
--- a/src/fspec/validator.rl
+++ /dev/null
@@ -1,236 +0,0 @@
-#include "ragel/ragel.h"
-#include <fspec/bcode.h>
-#include <fspec/validator.h>
-#include "bcode-internal.h"
-
-#include <assert.h>
-
-struct stack {
-   union {
-      fspec_num num;
-      fspec_off off;
-      fspec_var var;
-      fspec_strsz strsz;
-      unsigned char b[sizeof(fspec_num)];
-   } u;
-   uint8_t i; // writing index for u.b
-};
-
-struct range {
-   fspec_off start, end;
-};
-
-struct context {
-   struct range data;
-   fspec_var declarations, expected_declarations;
-   fspec_off str_end, decl_start, decl_end[FSPEC_DECLARATION_LAST], offset;
-   enum fspec_declaration last_decl_type;
-};
-
-struct state {
-   struct ragel ragel;
-   struct context context;
-   struct stack stack;
-};
-
-%%{
-   machine fspec_validator;
-   variable p state.ragel.p;
-   variable pe state.ragel.pe;
-   variable eof state.ragel.eof;
-   write data noerror nofinal;
-
-   action store_decls {
-      if (state.stack.u.num > (fspec_var)~0)
-         ragel_throw_error(&state.ragel, "expected declarations overflows");
-
-      state.context.expected_declarations = state.stack.u.num;
-   }
-
-   action check_decls {
-      if (state.context.declarations != state.context.expected_declarations)
-         ragel_throw_error(&state.ragel, "expected declarations did not match with the content: expected: %" PRI_FSPEC_VAR " got: %" PRI_FSPEC_VAR, state.context.expected_declarations, state.context.declarations);
-   }
-
-   action mark_dat {
-      // we can replace this logic with fspec generated code in future
-      // struct str { len: u32; str: u8[len]['\0']; }
-      // struct dat { len: u32; strings: struct str[$::len]; }
-      if (state.context.offset > (fspec_off)~0 - state.stack.u.off)
-         ragel_throw_error(&state.ragel, "dat section length overflows");
-
-      state.context.data = (struct range){ .start = state.context.offset, .end = state.stack.u.off };
-   }
-
-   action test_inside_dat {
-      state.context.offset < (state.context.data.start + state.context.data.end)
-   }
-
-   action mark_str {
-      if (state.context.offset >= (fspec_off)~0 - state.stack.u.strsz) // >= for null byte
-         ragel_throw_error(&state.ragel, "str length overflows");
-
-      state.context.str_end = state.context.offset + state.stack.u.strsz;
-   }
-
-   action test_inside_str {
-      state.context.offset < state.context.str_end
-   }
-
-   action check_var {
-      if (state.context.declarations <= state.stack.u.var)
-         ragel_throw_error(&state.ragel, "refenced undeclared variable");
-   }
-
-   action check_str {
-      if (state.stack.u.off < state.context.data.start) {
-         ragel_throw_error(&state.ragel, "str before data section range: %" PRI_FSPEC_OFF " <= %" PRI_FSPEC_OFF, state.stack.u.off, state.context.data.start + state.context.data.end);
-      } else if (state.context.data.start + state.context.data.end <= state.stack.u.off) {
-         ragel_throw_error(&state.ragel, "str after data section range: %" PRI_FSPEC_OFF " <= %" PRI_FSPEC_OFF, state.context.data.start + state.context.data.end, state.stack.u.off);
-      }
-   }
-
-   action check_decl_type {
-      if (state.stack.u.num >= FSPEC_DECLARATION_LAST)
-         ragel_throw_error(&state.ragel, "invalid declaration type: %" PRI_FSPEC_NUM, state.stack.u.num);
-
-      state.context.last_decl_type = state.stack.u.num;
-   }
-
-   action check_decl_num {
-      if (state.context.declarations >= (fspec_var)~0)
-         ragel_throw_error(&state.ragel, "declarations overflows");
-
-      if (state.context.declarations != state.stack.u.num)
-         ragel_throw_error(&state.ragel, "invalid declaration number: %" PRI_FSPEC_NUM " expected: %" PRI_FSPEC_VAR, state.stack.u.num, state.context.declarations);
-
-      ++state.context.declarations;
-   }
-
-   action start_decl {
-      state.context.decl_start = state.context.offset;
-   }
-
-   action mark_decl {
-      const fspec_off sz = (state.context.offset - state.context.decl_start);
-      assert(sz <= state.stack.u.off);
-
-      if (state.context.offset > (fspec_off)~0 - state.stack.u.off - sz)
-         ragel_throw_error(&state.ragel, "declaration length overflows");
-
-      state.context.decl_end[state.context.last_decl_type] = state.context.offset + state.stack.u.off - sz;
-   }
-
-   action check_struct {
-      if (state.context.last_decl_type != FSPEC_DECLARATION_STRUCT)
-         ragel_throw_error(&state.ragel, "expected struct declaration");
-   }
-
-   action check_member {
-      if (state.context.last_decl_type != FSPEC_DECLARATION_MEMBER)
-         ragel_throw_error(&state.ragel, "expected member declaration");
-   }
-
-   action check_member_end {
-      if (state.context.decl_end[FSPEC_DECLARATION_MEMBER] != state.context.offset)
-         ragel_throw_error(&state.ragel, "invalid member end: %" PRI_FSPEC_OFF " expected: %" PRI_FSPEC_OFF, state.context.decl_end[FSPEC_DECLARATION_MEMBER], state.context.offset);
-   }
-
-   action check_struct_end {
-      if (state.context.decl_end[FSPEC_DECLARATION_STRUCT] != state.context.offset)
-         ragel_throw_error(&state.ragel, "invalid struct end: %" PRI_FSPEC_OFF " expected: %" PRI_FSPEC_OFF, state.context.decl_end[FSPEC_DECLARATION_STRUCT], state.context.offset);
-   }
-
-   action check_visual_type {
-      if (state.stack.u.num >= FSPEC_VISUAL_LAST)
-         ragel_throw_error(&state.ragel, "invalid visual type: %" PRI_FSPEC_NUM, state.stack.u.num);
-   }
-
-   action arg_error {
-      ragel_throw_error(&state.ragel, "malformed argument");
-   }
-
-   action op_error {
-      ragel_throw_error(&state.ragel, "unexpected argument");
-   }
-
-   action pattern_error {
-      ragel_throw_error(&state.ragel, "unexpected pattern");
-   }
-
-   action syntax_error {
-      ragel_throw_error(&state.ragel, "unexpected byte");
-   }
-
-   action store {
-      if (state.stack.i < sizeof(state.stack.u.b))
-         state.stack.u.b[state.stack.i++] = fc;
-   }
-
-   action flush {
-      state.stack.i = 0;
-   }
-
-   action advance {
-      ++state.context.offset;
-   }
-
-   stack1 = any{1} >flush $store;
-   stack2 = any{2} >flush $store;
-   stack4 = any{4} >flush $store;
-   stack8 = any{8} >flush $store;
-
-   ARG_DAT = 0 stack4 %*mark_dat ((stack1 %*mark_str (any when test_inside_str)* 0) when test_inside_dat)*;
-   ARG_OFF = 1 stack4;
-   ARG_NUM = 2 stack8;
-   ARG_VAR = 3 stack2 %check_var;
-   ARG_STR = 4 stack4 %check_str;
-   ARG_EOF = 5;
-
-   OP_ARG_DAT = 0 ARG_DAT $!arg_error;
-   OP_ARG_OFF = 0 ARG_OFF $!arg_error;
-   OP_ARG_NUM = 0 ARG_NUM $!arg_error;
-   OP_ARG_VAR = 0 ARG_VAR $!arg_error;
-   OP_ARG_STR = 0 ARG_STR $!arg_error;
-   OP_ARG_EOF = 0 ARG_EOF $!arg_error;
-
-   OP_HEADER = 1 (OP_ARG_NUM OP_ARG_NUM %store_decls OP_ARG_DAT) $!op_error;
-   OP_DECLARATION = 2 >start_decl (OP_ARG_NUM %check_decl_type OP_ARG_NUM %check_decl_num OP_ARG_OFF %mark_decl OP_ARG_STR) $!op_error;
-   OP_READ = 3 (OP_ARG_NUM (OP_ARG_NUM | OP_ARG_VAR | OP_ARG_STR | OP_ARG_EOF)*) $!op_error;
-   OP_GOTO = 4 (OP_ARG_VAR (OP_ARG_NUM | OP_ARG_VAR | OP_ARG_STR | OP_ARG_EOF)*) $!op_error;
-   OP_FILTER = 5 (OP_ARG_STR (OP_ARG_NUM | OP_ARG_VAR | OP_ARG_STR)*) $!op_error;
-   OP_VISUAL = 6 (OP_ARG_NUM %check_visual_type) $!op_error;
-
-   pattern = (OP_DECLARATION %check_struct <: (OP_DECLARATION %check_member (OP_READ | OP_GOTO) OP_FILTER* OP_VISUAL? %check_member_end)*)* %check_struct_end $!pattern_error;
-   main := (OP_HEADER <: pattern) %check_decls $advance $!syntax_error;
-}%%
-
-bool
-fspec_validator_parse(struct fspec_validator *validator, const char *name)
-{
-   int cs;
-   %% write init;
-
-   (void)fspec_validator_en_main;
-   assert(validator);
-   assert(validator->ops.read);
-   assert(validator->mem.input.data && validator->mem.input.len);
-   assert(validator->mem.input.len <= (size_t)~0 && "input storage size exceeds size_t range");
-
-   struct state state = {
-      .ragel.name = name,
-      .ragel.lineno = 1,
-   };
-
-   static_assert(sizeof(state.stack.u) == sizeof(state.stack.u.b), "bytes doesn't represent the largest member in union");
-
-   struct fspec_mem input = validator->mem.input;
-   for (bool eof = false; !state.ragel.error && !eof;) {
-      const size_t bytes = validator->ops.read(validator, input.data, 1, input.len);
-      const struct ragel_mem rl = { .data = input.data, .end = (char*)input.data + bytes, .binary = true };
-      ragel_feed_input(&state.ragel, (eof = (bytes < input.len)), &rl);
-      %% write exec;
-   }
-
-   return !state.ragel.error;
-}
diff --git a/src/util/membuf.c b/src/util/membuf.c
new file mode 100644
index 0000000..0602679
--- /dev/null
+++ b/src/util/membuf.c
@@ -0,0 +1,31 @@
+#include "membuf.h"
+
+#include <stdlib.h>
+#include <assert.h>
+#include <memory.h>
+#include <err.h>
+
+static void
+membuf_bounds_check(const struct membuf *buf, const size_t nmemb)
+{
+   assert(buf);
+
+   if (buf->mem.len < nmemb || buf->written > buf->mem.len - nmemb)
+      errx(EXIT_FAILURE, "%s: %zu bytes exceeds the maximum storage size of %zu bytes", __func__, buf->written + nmemb, buf->mem.len);
+}
+
+void
+membuf_terminate(struct membuf *buf, const void *data, const size_t data_sz)
+{
+   assert(data || !data_sz);
+   membuf_bounds_check(buf, data_sz);
+   memcpy((char*)buf->mem.data + buf->written, data, data_sz);
+}
+
+void
+membuf_append(struct membuf *buf, const void *data, const size_t data_sz)
+{
+   membuf_terminate(buf, data, data_sz);
+   buf->written += data_sz;
+   assert(buf->written <= buf->mem.len);
+}
diff --git a/src/util/membuf.h b/src/util/membuf.h
new file mode 100644
index 0000000..86d8dde
--- /dev/null
+++ b/src/util/membuf.h
@@ -0,0 +1,14 @@
+#pragma once
+
+#include <fspec/memory.h>
+
+struct membuf {
+   struct fspec_mem mem;
+   size_t written;
+};
+
+void
+membuf_terminate(struct membuf *buf, const void *data, const size_t data_sz);
+
+void
+membuf_append(struct membuf *buf, const void *data, const size_t data_sz);
diff --git a/src/ragel/ragel.h b/src/util/ragel/ragel.h
index b2c7572..b2c7572 100644
--- a/src/ragel/ragel.h
+++ b/src/util/ragel/ragel.h
diff --git a/src/ragel/ragel.rl b/src/util/ragel/ragel.rl
index 7e51030..c52f27b 100644
--- a/src/ragel/ragel.rl
+++ b/src/util/ragel/ragel.rl
@@ -1,4 +1,5 @@
 #include "ragel.h"
+
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdarg.h>