From d0d8ae007bd6afcda2b72ab53d3567d660593241 Mon Sep 17 00:00:00 2001
From: "Chloe M." <chloe@mirocom.org>
Date: Mon, 25 May 2026 00:12:32 -0500
Subject: parser: Add initial preprocessing macro parsing

Signed-off-by: Chloe M. <chloe@mirocom.org>
---
 core/parser.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 82 insertions(+), 3 deletions(-)

(limited to 'core')

diff --git a/core/parser.c b/core/parser.c
index a438b74..fb8d817 100644
--- a/core/parser.c
+++ b/core/parser.c
@@ -26,6 +26,14 @@
 #define tokstr(tok) \
     toktab[(tok)->type]
 
+/* Unexpected token */
+#define utok(tok)           \
+    cc_error("unexpected token %s\n", tokstr(tok));
+#define utok1(tok, exp_tt)  \
+    cc_error("unexpected token %s, expected %s\n", tokstr(tok), tokstr1(exp_tt))
+
+static int parser_expect(struct cescal_state *state, struct token *res, tt_t exp);
+
 /*
  * Converts numeric tokens into human readable strings
  */
@@ -58,16 +66,51 @@ static const char *toktab[] = {
     [TT_U64]     = qtok("u64")
 };
 
+
+/*
+ * Parse a preprocessor define directive
+ */
+static int
+parse_define(struct cescal_state *state, struct token *tok)
+{
+    struct symbol *sym;
+    int error;
+
+    if (state == NULL || tok == NULL) {
+        return -1;
+    }
+
+    if (parser_expect(state, tok, TT_IDENT) < 0) {
+        return -1;
+    }
+
+    /* XXX: Should probably be a warning */
+    if ((sym = symbol_byname(&state->symtab, tok->s)) != NULL) {
+        cc_error("redefinition of symbol %s\n", tok->s);
+        return -1;
+    }
+
+    /* Allocate the symbol */
+    error = symbol_allocate(&state->symtab, tok->s, SYMBOL_NONE, &sym);
+    if (error < 0) {
+        cc_error("[internal]: failed to allocate symbol\n");
+        return -1;
+    }
+
+    return 0;
+}
+
 /*
  * Push a token to the token buffer in the preprocessing stage
  *
+ * @state:  Compiler state
  * @tokbuf: Token buffer to push to
  * @tok:    Token to push
  *
  * Returns zero on success
  */
 static int
-preprocessor_push(struct tokbuf *tokbuf, struct token *tok)
+preprocessor_push(struct cescal_state *state, struct tokbuf *tokbuf, struct token *tok)
 {
     if (tokbuf == NULL || tok == NULL) {
         return -1;
@@ -75,8 +118,14 @@ preprocessor_push(struct tokbuf *tokbuf, struct token *tok)
 
     switch (tok->type) {
     case TT_IFNDEF:
+        break;
     case TT_IFDEF:
+        break;
     case TT_DEFINE:
+        if (parse_define(state, tok) < 0) {
+            return -1;
+        }
+
         break;
     default:
         if (tokbuf_push(tokbuf, tok) < 0) {
@@ -114,7 +163,35 @@ parser_nom(struct cescal_state *state, struct token *res)
         break;
     }
 
-    *res = tok;
+    return 0;
+}
+
+/*
+ * Assert that the next token is of a specific type
+ *
+ * @state:   Compiler state
+ * @res:     Token result is written here
+ * @exp:     Token expedcted
+ *
+ * Returns zero on success
+ */
+static int
+parser_expect(struct cescal_state *state, struct token *res, tt_t exp)
+{
+    if (state == NULL || res == NULL) {
+        return -1;
+    }
+
+    if (parser_nom(state, res) < 0) {
+        cc_error("unexpected end of file\n");
+        return -1;
+    }
+
+    if (res->type != exp) {
+        utok1(res, exp);
+        return -1;
+    }
+
     return 0;
 }
 
@@ -129,7 +206,9 @@ parser_parse(struct cescal_state *state)
     }
 
     while (parser_nom(state, &tok) == 0) {
-        cc_trace("got token %s\n", tokstr(&tok));
+        if (state->pass > 0) {
+            cc_trace("got token %s\n", tokstr(&tok));
+        }
     }
 
     ++state->pass;
-- 
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