From 6d7c58a512f821aabed87b61f2777568e1b3aab1 Mon Sep 17 00:00:00 2001
From: overflowerror <mail@overflowerror.com>
Date: Sat, 27 Apr 2024 17:08:12 +0200
Subject: [PATCH] fix: newline escapes in char literal

---
 compiler/src/lexer.l                             | 15 +++++++++++++--
 compiler/test/cases/001a-bug-newline-in-char.in  |  1 +
 compiler/test/cases/001a-bug-newline-in-char.out |  1 +
 3 files changed, 15 insertions(+), 2 deletions(-)
 create mode 100644 compiler/test/cases/001a-bug-newline-in-char.in
 create mode 100644 compiler/test/cases/001a-bug-newline-in-char.out

diff --git a/compiler/src/lexer.l b/compiler/src/lexer.l
index 361ae4a..b52b345 100644
--- a/compiler/src/lexer.l
+++ b/compiler/src/lexer.l
@@ -10,7 +10,7 @@ if      "if"
 else    "else"
 while   "while"
 
-char    "'"."'"
+char    "'"([^\\]|[\\]n|[\\]t|[\\]{2})"'"
 id		[a-zA-Z_][a-zA-Z0-9_]*
 
 %option noyywrap
@@ -34,6 +34,17 @@ id		[a-zA-Z_][a-zA-Z0-9_]*
 
 #include "y.tab.h"
 
+char char_escape(const char* yytext) {
+    if (yytext[1] == '\\') {
+        if (yytext[2] == '\\')     return '\\';
+        else if (yytext[2] == 'n') return '\n';
+        else if (yytext[2] == 't') return '\t';
+        else lex_panic("unknown escape sequence: %s\n", yytext);
+    } else {
+        return yytext[1];
+    }
+}
+
 %}
 
 %%
@@ -106,7 +117,7 @@ strbuf_t strbuf = NULL;
 <INITIAL>{dec}		{ yylval.number = strtol(yytext, NULL, 10); return NUM; }
 <INITIAL>{oct}		{ yylval.number = strtol(yytext + 1, NULL, 8); return NUM; }
 <INITIAL>{bin}		{ yylval.number = strtol(yytext + 2, NULL, 2); return NUM; }
-<INITIAL>{char}		{ yylval.ch = yytext[1]; return CHAR; }
+<INITIAL>{char}		{ yylval.ch = char_escape(yytext); return CHAR; }
 <INITIAL>{id}		{ yylval.id = strdup(yytext); return ID; }
 <INITIAL>{whitespace}+	{ }
 
diff --git a/compiler/test/cases/001a-bug-newline-in-char.in b/compiler/test/cases/001a-bug-newline-in-char.in
new file mode 100644
index 0000000..0a74cff
--- /dev/null
+++ b/compiler/test/cases/001a-bug-newline-in-char.in
@@ -0,0 +1 @@
+print('\n');
\ No newline at end of file
diff --git a/compiler/test/cases/001a-bug-newline-in-char.out b/compiler/test/cases/001a-bug-newline-in-char.out
new file mode 100644
index 0000000..34f0ecc
--- /dev/null
+++ b/compiler/test/cases/001a-bug-newline-in-char.out
@@ -0,0 +1 @@
+[-]++++++++++.