From eb22f9bbc2f2596c2c690960852e29eaed04ea09 Mon Sep 17 00:00:00 2001
From: nsfisis <nsfisis@gmail.com>
Date: Tue, 19 Aug 2025 07:51:50 +0900
Subject: feat: skip a pair of backslash and new-line

---
 io.c         | 18 ++++++++++++++++++
 tests/096.sh | 41 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+)
 create mode 100644 tests/096.sh

diff --git a/io.c b/io.c
index c6e94d1..dcfbd08 100644
--- a/io.c
+++ b/io.c
@@ -57,6 +57,24 @@ BOOL infile_eof(InFile* f) {
 
 char infile_peek_char(InFile* f) {
     char c = f->buf[f->pos];
+
+    // Skip a pair of backslash and new-line.
+    if (c == '\\') {
+        char c2 = f->buf[f->pos + 1];
+        // C23: 5.1.1.2
+        // A source file that is not empty shall end in a new-line character,
+        // which shall not be immediately preceded by a backslash character
+        // before any such splicing takes place.
+        if (c2 == '\0') {
+            fatal_error("%s:%d: <new-line> expected, but got <eof>", f->loc.filename, f->loc.line);
+        }
+        // TODO: crlf
+        if (c2 == '\r' || c2 == '\n') {
+            f->pos += 2;
+            return infile_peek_char(f);
+        }
+    }
+
     // Normalize new-line.
     // TODO: crlf
     if (c == '\r')
diff --git a/tests/096.sh b/tests/096.sh
new file mode 100644
index 0000000..8bd6848
--- /dev/null
+++ b/tests/096.sh
@@ -0,0 +1,41 @@
+set -e
+
+cat <<'EOF' > expected
+10 20
+100 300 500
+EOF
+
+bash ../../test_diff.sh <<'EOF'
+int printf();
+in\
+t ma\
+in() {
+    int x = 1\
+0;
+
+    int y = 2\
+\
+\
+0;
+
+#def\
+ine X 100
+#define Y 100 + \
+200
+#define Z /*
+*/ 500
+    // comment \
+    x *= 100, y *= 200;
+    /* comment *\
+/
+
+    printf("%d %d\n", x, y);
+    printf("%d %d %d\n", X, Y, Z);
+}
+EOF
+
+cat <<'EOF' > expected
+main.c:1: <new-line> expected, but got <eof>
+EOF
+
+echo -n 'int main() {}\' | bash ../../test_compile_error.sh
-- 
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