Add string replace function

stdlib/std.jsonnet

@@ -98,6 +98,32 @@ limitations under the License.
                     aux(str, delim, i2, arr, v + c) tailstrict;
             aux(str, c, 0, [], ""),
 
+    strReplace(str, from, to)::
+        assert std.type(str) == "string";
+        assert std.type(from) == "string";
+        assert std.type(to) == "string";
+        assert from != "" : "'from' string must not be zero length.";
+
+        // Cache for performance.
+        local str_len = std.length(str);
+        local from_len = std.length(from);
+
+        // True if from is at str[i].
+        local found_at(i) = str[i:i + from_len] == from;
+
+        // Return the remainder of 'str' starting with 'start_index' where
+        // all occurrences of 'from' after 'curr_index' are replaced with 'to'.
+        local replace_after(start_index, curr_index, acc) =
+            if curr_index > str_len then
+                acc + str[start_index:curr_index]
+            else if found_at(curr_index) then
+                local new_index = curr_index + std.length(from);
+                replace_after(new_index, new_index, acc + str[start_index:curr_index] + to)
+            else
+                replace_after(start_index, curr_index + 1, acc);
+
+        replace_after(0, 0, ""),
+
     range(from, to)::
         std.makeArray(to - from + 1, function(i) i + from),
 

test_suite/error.equality_function.jsonnet.golden

@@ -1,3 +1,3 @@
 RUNTIME ERROR: Cannot test equality of functions
-	std.jsonnet:1014:17-42	function <anonymous>
+	std.jsonnet:1040:17-42	function <anonymous>
 	error.equality_function.jsonnet:17:1-33	

test_suite/error.inside_equals_array.jsonnet.golden

@@ -1,7 +1,7 @@
 RUNTIME ERROR: foobar
 	error.inside_equals_array.jsonnet:18:18-32	thunk <array_element>
-	std.jsonnet:994:41-45	thunk <b>
-	std.jsonnet:994:33-45	function <anonymous>
-	std.jsonnet:994:33-45	function <aux>
-	std.jsonnet:997:29-45	function <anonymous>
-	std.jsonnet:998:21-33	
+	std.jsonnet:1020:41-45	thunk <b>
+	std.jsonnet:1020:33-45	function <anonymous>
+	std.jsonnet:1020:33-45	function <aux>
+	std.jsonnet:1023:29-45	function <anonymous>
+	std.jsonnet:1024:21-33	

test_suite/error.inside_equals_object.jsonnet.golden

@@ -1,7 +1,7 @@
 RUNTIME ERROR: foobar
 	error.inside_equals_object.jsonnet:18:22-36	object <b>
-	std.jsonnet:1008:62-66	thunk <b>
-	std.jsonnet:1008:54-66	function <anonymous>
-	std.jsonnet:1008:54-66	function <aux>
-	std.jsonnet:1011:29-45	function <anonymous>
-	std.jsonnet:1012:21-33	
+	std.jsonnet:1034:62-66	thunk <b>
+	std.jsonnet:1034:54-66	function <anonymous>
+	std.jsonnet:1034:54-66	function <aux>
+	std.jsonnet:1037:29-45	function <anonymous>
+	std.jsonnet:1038:21-33	

test_suite/error.invariant.equality.jsonnet.golden

@@ -1,6 +1,6 @@
 RUNTIME ERROR: Object assertion failed.
 	error.invariant.equality.jsonnet:17:10-15	thunk <object_assert>
-	std.jsonnet:1008:54-58	thunk <a>
-	std.jsonnet:1008:54-66	function <anonymous>
-	std.jsonnet:1008:54-66	function <anonymous>
-	std.jsonnet:1012:21-33	
+	std.jsonnet:1034:54-58	thunk <a>
+	std.jsonnet:1034:54-66	function <anonymous>
+	std.jsonnet:1034:54-66	function <anonymous>
+	std.jsonnet:1038:21-33	

test_suite/error.obj_assert.fail1.jsonnet.golden

@@ -1,6 +1,6 @@
 RUNTIME ERROR: Object assertion failed.
 	error.obj_assert.fail1.jsonnet:20:23-29	thunk <object_assert>
-	std.jsonnet:1008:54-58	thunk <a>
-	std.jsonnet:1008:54-66	function <anonymous>
-	std.jsonnet:1008:54-66	function <anonymous>
-	std.jsonnet:1012:21-33	
+	std.jsonnet:1034:54-58	thunk <a>
+	std.jsonnet:1034:54-66	function <anonymous>
+	std.jsonnet:1034:54-66	function <anonymous>
+	std.jsonnet:1038:21-33	

test_suite/error.obj_assert.fail2.jsonnet.golden

@@ -1,6 +1,6 @@
 RUNTIME ERROR: foo was not equal to bar
 	error.obj_assert.fail2.jsonnet:20:32-65	thunk <object_assert>
-	std.jsonnet:1008:54-58	thunk <a>
-	std.jsonnet:1008:54-66	function <anonymous>
-	std.jsonnet:1008:54-66	function <anonymous>
-	std.jsonnet:1012:21-33	
+	std.jsonnet:1034:54-58	thunk <a>
+	std.jsonnet:1034:54-66	function <anonymous>
+	std.jsonnet:1034:54-66	function <anonymous>
+	std.jsonnet:1038:21-33	

test_suite/error.sanity.jsonnet.golden

@@ -1,3 +1,3 @@
 RUNTIME ERROR: Assertion failed. 1 != 2
-	std.jsonnet:651:13-56	function <anonymous>
+	std.jsonnet:677:13-56	function <anonymous>
 	error.sanity.jsonnet:17:1-22	

test_suite/error.std_join_types1.jsonnet.golden

@@ -1,5 +1,5 @@
 RUNTIME ERROR: expected string but arr[1] was array 
-	std.jsonnet:167:17-95	function <aux>
-	std.jsonnet:169:17-57	function <aux>
-	std.jsonnet:175:13-34	function <anonymous>
+	std.jsonnet:193:17-95	function <aux>
+	std.jsonnet:195:17-57	function <aux>
+	std.jsonnet:201:13-34	function <anonymous>
 	error.std_join_types1.jsonnet:17:1-26	

test_suite/error.std_join_types2.jsonnet.golden

@@ -1,4 +1,4 @@
 RUNTIME ERROR: expected array but arr[0] was string 
-	std.jsonnet:167:17-95	function <aux>
-	std.jsonnet:177:13-34	function <anonymous>
+	std.jsonnet:193:17-95	function <aux>
+	std.jsonnet:203:13-34	function <anonymous>
 	error.std_join_types2.jsonnet:17:1-31	

test_suite/stdlib.jsonnet

@@ -159,6 +159,14 @@ std.assertEqual(std.char(97), "a") &&
 std.assertEqual(std.codepoint("\u0000"), 0) &&
 std.assertEqual(std.char(0), "\u0000") &&
 
+std.assertEqual(std.strReplace('A cat walked by', 'cat', 'dog'), 'A dog walked by') &&
+std.assertEqual(std.strReplace('cat', 'cat', 'dog'), 'dog') &&
+std.assertEqual(std.strReplace('', 'cat', ''), '') &&
+std.assertEqual(std.strReplace('xoxoxoxox', 'xoxox3xox', 'A'), 'xoxoxoxox') &&
+std.assertEqual(std.strReplace('xoxoxox3xox', 'xoxox3xox', 'A'), 'xoA') &&
+std.assertEqual(std.strReplace('A cat is a cat', 'cat', 'dog'), 'A dog is a dog') &&
+std.assertEqual(std.strReplace('wishyfishyisishy', 'ish', 'and'), 'wandyfandyisandy') &&
+
 std.assertEqual(std.map(function(x) x * x, []), []) &&
 std.assertEqual(std.map(function(x) x * x, [1, 2, 3, 4]), [1, 4, 9, 16]) &&
 std.assertEqual(std.map(function(x) x * x, std.filter(function(x) x > 5, std.range(1, 10))), [36, 49, 64, 81, 100]) &&