feat: implement extern block reading and parsing

src/compiler/parser/pa_extern.c

@@ -0,0 +1,192 @@
+#include <compiler/fzl_parser.h>
+#include <compiler/fzl_token.h>
+#include <compiler/internals/parser.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+// Parse extern definition
+fzl_node_t *pa_extern(fzl_parser_t *parser)
+{
+  if (!parser || !peek(parser))
+    return NULL;
+
+  fzl_token_t *kw = consume(parser);
+  if (!kw || kw->type != FZL_TOKTYPE_EXTERN)
+  {
+    snprintf(plast_err, sizeof(plast_err),
+             "'%s':%zu:%zu => expected 'extern' keyword",
+             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
+    return NULL;
+  }
+
+  fzl_token_t *libname = consume(parser);
+  if (!libname || libname->type != FZL_TOKTYPE_STR_LITERAL)
+  {
+    snprintf(plast_err, sizeof(plast_err),
+             "'%s':%zu:%zu => expected library name after 'extern'",
+             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
+    return NULL;
+  }
+
+  fzl_token_t *lbra = consume(parser);
+  if (!lbra || lbra->type != FZL_TOKTYPE_LBRACE)
+  {
+    snprintf(plast_err, sizeof(plast_err),
+             "'%s':%zu:%zu => expected '{' after library name",
+             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
+    return NULL;
+  }
+
+  // Typedefs array
+  size_t td_remainder = 2;
+  size_t td_count     = 0;
+  fzl_node_t **td     = malloc(td_remainder * sizeof(fzl_node_t *));
+  if (!td)
+  {
+    snprintf(plast_err, sizeof(plast_err), "out of memory");
+    return NULL;
+  }
+
+  // Functions array
+  size_t fn_remainder = 2;
+  size_t fn_count     = 0;
+  fzl_node_t **fn     = malloc(fn_remainder * sizeof(fzl_node_t *));
+  if (!fn)
+  {
+    free(td);
+    snprintf(plast_err, sizeof(plast_err), "out of memory");
+    return NULL;
+  }
+
+  bool error = false;
+  while (peek(parser))
+  {
+    if (is(parser, FZL_TOKTYPE_RBRACE))
+      break;
+
+    if (td_remainder <= td_count)
+    {
+      td_remainder *= 2;
+      fzl_node_t **newarr = realloc(td, td_remainder * sizeof(fzl_node_t *));
+      if (!newarr)
+      {
+        snprintf(plast_err, sizeof(plast_err), "out of memory");
+        error = true;
+        break;
+      }
+
+      td = newarr;
+    }
+
+    if (fn_remainder <= fn_count)
+    {
+      fn_remainder *= 2;
+      fzl_node_t **newarr = realloc(fn, fn_remainder * sizeof(fzl_node_t *));
+      if (!newarr)
+      {
+        snprintf(plast_err, sizeof(plast_err), "out of memory");
+        error = true;
+        break;
+      }
+
+      fn = newarr;
+    }
+
+    if (is(parser, FZL_TOKTYPE_TYPEDEF))
+    {
+      fzl_node_t *result = pa_typedef(parser);
+      if (!result)
+      {
+        error = true;
+        break;
+      }
+
+      td[td_count++] = result;
+    }
+    else if (is(parser, FZL_TOKTYPE_FUNCTION))
+    {
+      fzl_node_t *result = pa_externfn(parser);
+      if (!result)
+      {
+        error = true;
+        break;
+      }
+
+      fn[fn_count++] = result;
+    }
+    else
+    {
+      snprintf(plast_err, sizeof(plast_err),
+               "'%s':%zu:%zu => unexpected statement inside extern block",
+               last_known_tok->filename, last_known_tok->ln,
+               last_known_tok->cn);
+      error = true;
+      break;
+    }
+
+    fzl_token_t *sc = consume(parser);
+    if (!sc || sc->type != FZL_TOKTYPE_SEMICOLON)
+    {
+      snprintf(plast_err, sizeof(plast_err), "'%s':%zu:%zu => missing ';'",
+               last_known_tok->filename, last_known_tok->ln,
+               last_known_tok->cn);
+      error = true;
+      break;
+    }
+  }
+
+  if (error)
+  {
+    for (size_t i = 0; i < td_count; i++)
+      fzl_freeast(td[i]);
+    free(td);
+
+    for (size_t i = 0; i < fn_count; i++)
+      fzl_freeast(fn[i]);
+    free(fn);
+
+    return NULL;
+  }
+
+  fzl_token_t *rbra = consume(parser);
+  if (!rbra || rbra->type != FZL_TOKTYPE_RBRACE)
+  {
+    for (size_t i = 0; i < td_count; i++)
+      fzl_freeast(td[i]);
+    free(td);
+
+    for (size_t i = 0; i < fn_count; i++)
+      fzl_freeast(fn[i]);
+    free(fn);
+
+    snprintf(plast_err, sizeof(plast_err),
+             "'%s':%zu:%zu => expected '}' after extern block",
+             last_known_tok->filename, last_known_tok->ln, last_known_tok->cn);
+    return NULL;
+  }
+
+  fzl_node_t *node = fzl_mknode(FZL_NODETYPE_EXTERN, kw);
+  if (!node)
+  {
+    for (size_t i = 0; i < td_count; i++)
+      fzl_freeast(td[i]);
+    free(td);
+
+    for (size_t i = 0; i < fn_count; i++)
+      fzl_freeast(fn[i]);
+    free(fn);
+
+    snprintf(plast_err, sizeof(plast_err), "out of memory");
+    return NULL;
+  }
+
+  node->ext.libname        = (char *)libname->value;
+  node->ext.typedefs       = td;
+  node->ext.typedefs_count = td_count;
+  node->ext.fns            = fn;
+  node->ext.fns_count      = fn_count;
+
+  return node;
+}