From 581369c0836591a07b9b84b54042368db4d00cd5 Mon Sep 17 00:00:00 2001
From: dave caruso <me@paperdave.net>
Date: Mon, 16 Sep 2024 03:32:36 -0400
Subject: [PATCH] feat: implement multiline string literals

---
 CHANGELOG.md           |  1 +
 src/core/Parse.zig     | 18 ++++++++++++++++++
 src/core/Transform.zig | 22 ++++++++++++++++++++++
 test/behavior/string   | 14 ++++++++++++++
 4 files changed, 55 insertions(+)
 create mode 100644 test/behavior/string

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4fd3a46010f6e891a8b671348cce1db15e4084c6..40108791e1dda71a087b2605b09cf94cdebcfafe 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@
 - feat: rename `noreturn` to `never`
 - feat: allow instantiating `@extern` at compile time
 - feat: implement tuples
+- feat: implement multiline string literals
 - fix: crash when printing unused struct declaration error
 - fix: provide array result type to sema
 - fix: crash when analyzing an empty array without a result type
diff --git a/src/core/Parse.zig b/src/core/Parse.zig
index 120626eac16464a5bea13eff869cf72a4757c3d0..64e69aea245518ba9812947cd904e9e7882af9f3 100644
--- a/src/core/Parse.zig
+++ b/src/core/Parse.zig
@@ -819,6 +819,7 @@ fn isExpressionStart(p: *Parse) bool {
         .kw_fn,
         .kw_struct,
         .kw_tuple,
+        .multiline_string,
         => true,
         else => false,
     };
@@ -877,6 +878,7 @@ fn parseExpressionPart(p: *Parse, mode: ParseExprMode) Error!NodeIndex {
         .number_int => try p.blankNode(.number_int),
         .number_float => try p.blankNode(.number_float),
         .string => try p.blankNode(.string),
+        .multiline_string => try p.parseMultilineString(),
 
         .builtin_id => try p.parseBuiltinCall(),
         .dot => try p.parseAnonStructInit(),
@@ -1320,6 +1322,22 @@ fn parseTupleType(p: *Parse) Error!NodeIndex {
     });
 }
 
+fn parseMultilineString(p: *Parse) !NodeIndex {
+    const start = p.assertToken(.multiline_string);
+
+    while (p.eatToken(.multiline_string) != null) {}
+
+    const len = p.pos - start;
+    return p.addNode(.{
+        .tag = .multiline_string,
+        .main_token = start,
+        .data = .{ .list = .{
+            .start = start,
+            .len = len,
+        } },
+    });
+}
+
 // helpers
 
 /// Append a node and return its index.
diff --git a/src/core/Transform.zig b/src/core/Transform.zig
index 4db0d59b9feab0f6da84f31d2a72b20038ada801..cbd8e9b1bae291405216f520e8c9b12e990fbb45 100644
--- a/src/core/Transform.zig
+++ b/src/core/Transform.zig
@@ -1620,6 +1620,28 @@ fn transformExpression(
             });
         },
 
+        .multiline_string => {
+            const token_list = t.ast.nodeData(node).list;
+
+            assert(t.id_decode_buf.items.len == 0);
+            defer t.id_decode_buf.clearRetainingCapacity();
+
+            try t.id_decode_buf.appendSlice(t.ast.tokenSlice(token_list.start)[2..]);
+            for (token_list.start + 1..token_list.start + token_list.len) |i| {
+                try t.id_decode_buf.append('\n');
+                try t.id_decode_buf.appendSlice(t.ast.tokenSlice(@intCast(i))[2..]);
+            }
+
+            return try t.addRef(.string, .{
+                .src_node = ctx.nodeOffset(node),
+                .extra_index = try t.extra.append(
+                    t.gpa,
+                    SlicedString,
+                    try t.addSlicedString(t.id_decode_buf.items),
+                ),
+            });
+        },
+
         else => |tag| std.debug.panic("TODO: expr {s}", .{@tagName(tag)}),
     }
 }
diff --git a/test/behavior/string b/test/behavior/string
new file mode 100644
index 0000000000000000000000000000000000000000..47fd2cea504cddc346094e766e0256c585f9fd79
--- /dev/null
+++ b/test/behavior/string
@@ -0,0 +1,14 @@
+let assertEqual = @extern("assertEqual");
+
+fn main {
+  assertEqual(
+    \\hello world
+    \\etc
+    \\
+    , "hello world\netc\n"
+  );
+  assertEqual(
+    \\language compiler
+    , "language compiler"
+  );
+}
-- 
2.54.0