From acabd99ee4195dac5083bfc2cbfd3bc58b4ec7c5 Mon Sep 17 00:00:00 2001
From: Rui Ueyama <ruiu@cs.stanford.edu>
Date: Sun, 11 Aug 2019 16:27:43 +0900
Subject: [PATCH] Add character literal

---
 test/literal.c | 10 ++++++++++
 tokenize.c     | 27 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 test/literal.c

diff --git a/test/literal.c b/test/literal.c
new file mode 100644
index 0000000..fd3ccf9
--- /dev/null
+++ b/test/literal.c
@@ -0,0 +1,10 @@
+#include "test.h"
+
+int main() {
+  ASSERT(97, 'a');
+  ASSERT(10, '\n');
+  ASSERT(-128, '\x80');
+
+  printf("OK\n");
+  return 0;
+}
diff --git a/tokenize.c b/tokenize.c
index 1d97568..eb7715f 100644
--- a/tokenize.c
+++ b/tokenize.c
@@ -205,6 +205,26 @@ static Token *read_string_literal(Token *cur, char *start) {
   return tok;
 }
 
+static Token *read_char_literal(Token *cur, char *start) {
+  char *p = start + 1;
+  if (*p == '\0')
+    error_at(start, "unclosed char literal");
+
+  char c;
+  if (*p == '\\')
+    c = read_escaped_char(&p, p + 1);
+  else
+    c = *p++;
+
+  char *end = strchr(p, '\'');
+  if (!end)
+    error_at(p, "unclosed char literal");
+
+  Token *tok = new_token(TK_NUM, cur, start, end - start + 1);
+  tok->val = c;
+  return tok;
+}
+
 static void convert_keywords(Token *tok) {
   for (Token *t = tok; t->kind != TK_EOF; t = t->next)
     if (is_keyword(t))
@@ -273,6 +293,13 @@ static Token *tokenize(char *filename, char *p) {
       continue;
     }
 
+    // Character literal
+    if (*p == '\'') {
+      cur = read_char_literal(cur, p);
+      p += cur->len;
+      continue;
+    }
+
     // Identifier or keyword
     if (is_ident1(*p)) {
       char *q = p++;
-- 
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