Refactor and begin parser

* Added token flags
* Added `int` keyword
* Moved code from main.c to parser/parser.c
* Began work on parsing declarations

Signed-off-by: Quinn Stephens <quinn@osmora.org>

4 files changed, 116 insertions, 37 deletions

diff --git a/src/lexer/keywords.c b/src/lexer/keywords.c
index 7bb6b47..30eb2a1 100644
--- a/src/lexer/keywords.c
+++ b/src/lexer/keywords.c
@@ -34,7 +34,7 @@
 #include "lexer/keywords.h"
 #include "log.h"
 
-#define KEYWORD_COUNT 1
+#define KEYWORD_COUNT 2
 
 #define KEYWORD_MAP_ROWS 16
 
@@ -43,13 +43,15 @@ static struct hashmap map;
 
 static struct {
     const char *str;
-    enum token_kind value;
+    enum token_kind tok_kind;
+    uint8_t tok_flags;
 } info[KEYWORD_COUNT] = {
-    { "void", TK_VOID }
+    { "void", TK_VOID, TF_BUILTIN_TYPE },
+    { "int" , TK_INT , TF_BUILTIN_TYPE }
 };
 
 static void
-add_keyword(const char *str, enum token_kind value)
+add_keyword(const char *str, enum token_kind tok_kind, uint8_t tok_flags)
 {
     struct keyword *kwd;
 
@@ -60,7 +62,8 @@ add_keyword(const char *str, enum token_kind value)
     }
 
     kwd->len = strlen(str);
-    kwd->value = value;
+    kwd->tok_kind = tok_kind;
+    kwd->tok_flags = tok_flags;
 
     kwd->hashmap_entry.hash = hash(str, kwd->len);
     hashmap_add(map, &kwd->hashmap_entry);
@@ -93,6 +96,6 @@ keywords_init(void)
 
     /* Register all keywords */
     for (int k = 0; k < KEYWORD_COUNT; k++) {
-        add_keyword(info[k].str, info[k].value);
+        add_keyword(info[k].str, info[k].tok_kind, info[k].tok_flags);
     }
 }
diff --git a/src/lexer/lexer.c b/src/lexer/lexer.c
index 183bd76..9be4cb1 100644
--- a/src/lexer/lexer.c
+++ b/src/lexer/lexer.c
@@ -63,7 +63,8 @@ lex_identifier(struct lexer *ctx, struct token *tok)
     /* Look for a keyword matching the identifier */
     kwd = keywords_find(tok);
     if (kwd != NULL) {
-        tok->kind = kwd->value;
+        tok->kind = kwd->tok_kind;
+        tok->flags |= kwd->tok_flags;
     } else {
         tok->kind = TK_IDENTIFIER;
     }
@@ -78,6 +79,7 @@ lexer_next(struct lexer *ctx, struct token *tok)
 
     skip_whitespace(ctx);
 
+    tok->flags = TF_NONE;
     tok->pos = ctx->pos;
     tok->line = ctx->line;
     tok->col = (int)(tok->pos - ctx->line_start) + 1;
diff --git a/src/main.c b/src/main.c
index e7a3225..c42239d 100644
--- a/src/main.c
+++ b/src/main.c
@@ -27,53 +27,28 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <stdarg.h>
-#include <stdio.h>
 #include <stdlib.h>
 #include "lexer.h"
 #include "log.h"
+#include "parser.h"
 
-static const char *src = "void main";
-
-static void
-tok_error(struct token *tok, const char *fmt, ...)
-{
-    va_list args;
-
-    fprintf(stderr, "\033[1;97m%d:%d: \033[1;91merror: \033[0m", tok->line, tok->col);
-    va_start(args, fmt);
-    vfprintf(stderr, fmt, args);
-    va_end(args);
-}
+static const char *src = "int test\nint main";
 
 int
 main(int argc, char **argv)
 {
     struct lexer lexer;
-    struct token tok;
 
     (void)argc;
     (void)argv;
 
     if (!lexer_init(&lexer, src)) {
+        log_error("Failed to initialize lexer\n");
         return EXIT_FAILURE;
     }
 
-    while (lexer_next(&lexer, &tok)) {
-        if (tok.kind == TK_EOF) {
-            return EXIT_SUCCESS;
-        }
-
-        if (tok.kind == TK_UNKNOWN) {
-            tok_error(&tok, "unrecognized token\n");
-            return EXIT_FAILURE;
-        }
-
-        if (tok.kind == TK_VOID) {
-            log_debug("got void\n");
-        } else if (tok.kind == TK_IDENTIFIER) {
-            log_debug("got identifier \"%.*s\"\n", tok.len, tok.pos);
-        }
+    if (!parser_parse(&lexer)) {
+        return EXIT_FAILURE;
     }
 
     return EXIT_SUCCESS;
diff --git a/src/parser/parser.c b/src/parser/parser.c
new file mode 100644
index 0000000..065bb32
--- /dev/null
+++ b/src/parser/parser.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2025 Quinn Stephens and the OSMORA team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS”
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdarg.h>
+#include <stdio.h>
+#include "lexer.h"
+#include "log.h"
+#include "parser.h"
+
+static void
+tok_error(struct token *tok, const char *fmt, ...)
+{
+    va_list args;
+
+    fprintf(stderr, "\033[1;97m%d:%d: \033[1;91merror: \033[0m", tok->line, tok->col);
+    va_start(args, fmt);
+    vfprintf(stderr, fmt, args);
+    va_end(args);
+}
+
+static bool
+parse_declaration(struct lexer *lexer, struct token *tok)
+{
+    /*
+     * TODO: Support more types.
+     */
+    if (tok->kind != TK_VOID && tok->kind != TK_INT) {
+        tok_error(tok, "expected \"void\" or \"int\"\n");
+        return false;
+    }
+
+    lexer_next(lexer, tok);
+    if (tok->kind != TK_IDENTIFIER) {
+        tok_error(tok, "expected identifier\n");
+        return false;
+    }
+
+    log_debug("Parsed declaration of \"%.*s\"\n", tok->len, tok->pos);
+
+    lexer_next(lexer, tok);
+    return true;
+}
+
+bool
+parser_parse(struct lexer *lexer)
+{
+    struct token tok;
+    bool success;
+
+    log_debug("Parsing...\n");
+
+    if (!lexer_next(lexer, &tok)) {
+        log_error("failed to get first token\n");
+        return false;
+    }
+
+    while (tok.kind != TK_EOF) {
+        if (tok.kind == TK_UNKNOWN) {
+            tok_error(&tok, "unrecognized token\n");
+            return false;
+        }
+
+        if ((tok.flags & TF_BUILTIN_TYPE) || tok.kind == TK_IDENTIFIER) {
+            success = parse_declaration(lexer, &tok);
+        }
+
+        if (!success) {
+            return false;
+        }
+    }
+
+    return true;
+}