Merge pull request #8437 from roc-lang/str-trim-start-end

add Str.trim_{start,end} builtins

Author: lukewilliamboswell

src/build/builtin_compiler/main.zig

@@ -107,6 +107,12 @@ fn replaceStrIsEmptyWithLowLevel(env: *ModuleEnv) !std.ArrayList(CIR.Def.Idx) {
     if (env.common.findIdent("Builtin.Str.trim")) |str_trim_ident| {
         try low_level_map.put(str_trim_ident, .str_trim);
     }
+    if (env.common.findIdent("Builtin.Str.trim_start")) |str_trim_start_ident| {
+        try low_level_map.put(str_trim_start_ident, .str_trim_start);
+    }
+    if (env.common.findIdent("Builtin.Str.trim_end")) |str_trim_end_ident| {
+        try low_level_map.put(str_trim_end_ident, .str_trim_end);
+    }
     if (env.common.findIdent("Builtin.Str.caseless_ascii_equals")) |str_caseless_ascii_equals_ident| {
         try low_level_map.put(str_caseless_ascii_equals_ident, .str_caseless_ascii_equals);
     }

src/build/roc/Builtin.roc

@@ -4,6 +4,8 @@ Builtin :: [].{
 		concat : Str, Str -> Str
 		contains : Str, Str -> Bool
 		trim : Str -> Str
+		trim_start : Str -> Str
+		trim_end : Str -> Str
 		caseless_ascii_equals : Str, Str -> Bool
 		with_ascii_lowercased : Str -> Str
 		with_ascii_uppercased : Str -> Str

src/canonicalize/Expression.zig

@@ -404,6 +404,8 @@ pub const Expr = union(enum) {
         str_concat,
         str_contains,
         str_trim,
+        str_trim_start,
+        str_trim_end,
         str_caseless_ascii_equals,
         str_with_ascii_lowercased,
         str_with_ascii_uppercased,

src/eval/interpreter.zig

@@ -2841,6 +2841,52 @@ pub const Interpreter = struct {
                 out.is_initialized = true;
                 return out;
             },
+            .str_trim_start => {
+                // Str.trim_start : Str -> Str
+                std.debug.assert(args.len == 1);
+
+                const str_arg = args[0];
+                std.debug.assert(str_arg.ptr != null);
+
+                const roc_str_arg: *const RocStr = @ptrCast(@alignCast(str_arg.ptr.?));
+
+                const result_str = builtins.str.strTrimStart(roc_str_arg.*, roc_ops);
+
+                // Allocate space for the result string
+                const result_layout = str_arg.layout; // Str layout
+                var out = try self.pushRaw(result_layout, 0);
+                out.is_initialized = false;
+
+                // Copy the result string structure to the output
+                const result_ptr: *RocStr = @ptrCast(@alignCast(out.ptr.?));
+                result_ptr.* = result_str;
+
+                out.is_initialized = true;
+                return out;
+            },
+            .str_trim_end => {
+                // Str.trim_end : Str -> Str
+                std.debug.assert(args.len == 1);
+
+                const str_arg = args[0];
+                std.debug.assert(str_arg.ptr != null);
+
+                const roc_str_arg: *const RocStr = @ptrCast(@alignCast(str_arg.ptr.?));
+
+                const result_str = builtins.str.strTrimEnd(roc_str_arg.*, roc_ops);
+
+                // Allocate space for the result string
+                const result_layout = str_arg.layout; // Str layout
+                var out = try self.pushRaw(result_layout, 0);
+                out.is_initialized = false;
+
+                // Copy the result string structure to the output
+                const result_ptr: *RocStr = @ptrCast(@alignCast(out.ptr.?));
+                result_ptr.* = result_str;
+
+                out.is_initialized = true;
+                return out;
+            },
             .str_caseless_ascii_equals => {
                 // Str.caseless_ascii_equals : Str, Str -> Bool
                 std.debug.assert(args.len == 2);

src/eval/test/low_level_interp_test.zig

@@ -537,6 +537,60 @@ test "e_low_level_lambda - Str.trim with a non-whitespace string" {
     try testing.expectEqualStrings("\"hello\"", value);
 }
 
+test "e_low_level_lambda - Str.trim_start with an empty string" {
+    const src =
+        \\x = Str.trim_start("")
+    ;
+    const value = try evalModuleAndGetString(src, 0, test_allocator);
+    defer test_allocator.free(value);
+    try testing.expectEqualStrings("\"\"", value);
+}
+
+test "e_low_level_lambda - Str.trim_start with a whitespace string" {
+    const src =
+        \\x = Str.trim_start("   ")
+    ;
+    const value = try evalModuleAndGetString(src, 0, test_allocator);
+    defer test_allocator.free(value);
+    try testing.expectEqualStrings("\"\"", value);
+}
+
+test "e_low_level_lambda - Str.trim_start with a non-whitespace string" {
+    const src =
+        \\x = Str.trim_start("  hello  ")
+    ;
+    const value = try evalModuleAndGetString(src, 0, test_allocator);
+    defer test_allocator.free(value);
+    try testing.expectEqualStrings("\"hello  \"", value);
+}
+
+test "e_low_level_lambda - Str.trim_end with an empty string" {
+    const src =
+        \\x = Str.trim_end("")
+    ;
+    const value = try evalModuleAndGetString(src, 0, test_allocator);
+    defer test_allocator.free(value);
+    try testing.expectEqualStrings("\"\"", value);
+}
+
+test "e_low_level_lambda - Str.trim_end with a whitespace string" {
+    const src =
+        \\x = Str.trim_end("   ")
+    ;
+    const value = try evalModuleAndGetString(src, 0, test_allocator);
+    defer test_allocator.free(value);
+    try testing.expectEqualStrings("\"\"", value);
+}
+
+test "e_low_level_lambda - Str.trim_end with a non-whitespace string" {
+    const src =
+        \\x = Str.trim_end("  hello  ")
+    ;
+    const value = try evalModuleAndGetString(src, 0, test_allocator);
+    defer test_allocator.free(value);
+    try testing.expectEqualStrings("\"  hello\"", value);
+}
+
 test "e_low_level_lambda - List.concat with two non-empty lists" {
     const src =
         \\x = List.concat([1, 2], [3, 4])

test/snapshots/repl/str_trim_end.md

@@ -0,0 +1,28 @@
+# META
+~~~ini
+description=Str.trim_end should work with various string combinations
+type=repl
+~~~
+# SOURCE
+~~~roc
+» Str.trim_end("  Hello")
+» Str.trim_end("Hello  ")
+» Str.trim_end("  Hello World  ")
+» Str.trim_end("Hello World")
+» Str.trim_end("    ")
+» Str.trim_end("")
+~~~
+# OUTPUT
+"  Hello"
+---
+"Hello"
+---
+"  Hello World"
+---
+"Hello World"
+---
+""
+---
+""
+# PROBLEMS
+NIL

test/snapshots/repl/str_trim_start.md

@@ -0,0 +1,28 @@
+# META
+~~~ini
+description=Str.trim_start should work with various string combinations
+type=repl
+~~~
+# SOURCE
+~~~roc
+» Str.trim_start("  Hello")
+» Str.trim_start("Hello  ")
+» Str.trim_start("  Hello World  ")
+» Str.trim_start("Hello World")
+» Str.trim_start("    ")
+» Str.trim_start("")
+~~~
+# OUTPUT
+"Hello"
+---
+"Hello  "
+---
+"Hello World  "
+---
+"Hello World"
+---
+""
+---
+""
+# PROBLEMS
+NIL