From 62451acdd4dd4cf369a801b0603e2e0841bfb627 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@mirocom.org>
Date: Sat, 23 May 2026 08:49:17 -0400
Subject: core: lexer: Add preprocessor tokens

Signed-off-by: Ian Moffett <ian@mirocom.org>
---
 core/lexer.c           | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++
 core/parser.c          |  3 +++
 include/cescal/token.h |  3 +++
 3 files changed, 58 insertions(+)

diff --git a/core/lexer.c b/core/lexer.c
index 1a62e71..6c7a4c9 100644
--- a/core/lexer.c
+++ b/core/lexer.c
@@ -189,6 +189,45 @@ lexer_check_kw(struct cescal_state *state, struct token *res)
     }
 }
 
+/*
+ * Check if an identifier token is actually a directive
+ *
+ * @state:   Compiler state
+ * @res:     Token result is written here
+ */
+static int
+lexer_check_direc(struct cescal_state *state, struct token *res)
+{
+    if (state == NULL || res == NULL) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    switch (*res->s) {
+    case 'd':
+        if (strcmp(res->s, "define") == 0) {
+            res->type = TT_DEFINE;
+            return 0;
+        }
+
+        break;
+    case 'i':
+        if (strcmp(res->s, "ifndef") == 0) {
+            res->type = TT_IFNDEF;
+            return 0;
+        }
+
+        if (strcmp(res->s, "ifdef") == 0) {
+            res->type = TT_IFDEF;
+            return 0;
+        }
+
+        break;
+    }
+
+    return -1;
+}
+
 /*
  * Skip anything after a comment
  *
@@ -236,6 +275,19 @@ lexer_nom(struct cescal_state *state, struct token *res)
     case ',':
         res->type = TT_COMMA;
         res->c = c;
+        return 0;
+    case '#':
+        if ((c = lexer_consume_single(state, true)) == '\0') {
+            return -1;
+        }
+
+        if (lexer_scan_ident(state, c, res) == 0) {
+            if (lexer_check_direc(state, res) != 0) {
+                cc_error("bad directive '%s'\n", res->s);
+                return -1;
+            }
+        }
+
         return 0;
     case '/':
         if (lexer_consume_single(state, true) == '/') {
diff --git a/core/parser.c b/core/parser.c
index 5d64bb7..684a1ff 100644
--- a/core/parser.c
+++ b/core/parser.c
@@ -38,6 +38,9 @@ static const char *toktab[] = {
     [TT_RPAREN]  = qtok(")"),
     [TT_COMMA]   = qtok(","),
     [TT_ARROW]   = qtok("->"),
+    [TT_DEFINE]  = qtok("#define"),
+    [TT_IFNDEF]  = qtok("#ifndef"),
+    [TT_IFDEF]   = qtok("#ifdef"),
     [TT_RETURN]  = qtok("return"),
     [TT_PUB]     = qtok("pub"),
     [TT_PROC]    = qtok("proc"),
diff --git a/include/cescal/token.h b/include/cescal/token.h
index e215371..21db2ac 100644
--- a/include/cescal/token.h
+++ b/include/cescal/token.h
@@ -18,6 +18,9 @@ typedef enum {
     TT_RPAREN,      /* '( */
     TT_COMMA,       /* ',' */
     TT_ARROW,       /* '->' */
+    TT_DEFINE,      /* '#define' */
+    TT_IFNDEF,      /* '#ifndef' */
+    TT_IFDEF,       /* '#ifdef' */
     TT_RETURN,      /* 'return' */
     TT_PUB,         /* 'pub' */
     TT_PROC,        /* 'proc' */
-- 
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