Remove regex functionality from rbcrun

As a first step to making .rbc files compatible with bazel,
remove regex support since bazel doesn't have it.

Fixes: 227384703
Test: ./out/rbcrun ./build/make/tests/run.rbc
Change-Id: I8b946c20cc42897a47a5516a167732f4e16b6158

tools/rbcrun/host.go

@@ -20,7 +20,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"regexp"
 	"strings"
 
 	"go.starlark.net/starlark"
@@ -125,23 +124,6 @@ func fileExists(_ *starlark.Thread, b *starlark.Builtin, args starlark.Tuple,
 	return starlark.True, nil
 }
 
-// regexMatch(pattern, s) returns True if s matches pattern (a regex)
-func regexMatch(_ *starlark.Thread, b *starlark.Builtin, args starlark.Tuple,
-	kwargs []starlark.Tuple) (starlark.Value, error) {
-	var pattern, s string
-	if err := starlark.UnpackPositionalArgs(b.Name(), args, kwargs, 2, &pattern, &s); err != nil {
-		return starlark.None, err
-	}
-	match, err := regexp.MatchString(pattern, s)
-	if err != nil {
-		return starlark.None, err
-	}
-	if match {
-		return starlark.True, nil
-	}
-	return starlark.False, nil
-}
-
 // wildcard(pattern, top=None) expands shell's glob pattern. If 'top' is present,
 // the 'top/pattern' is globbed and then 'top/' prefix is removed.
 func wildcard(_ *starlark.Thread, b *starlark.Builtin, args starlark.Tuple,
@@ -291,8 +273,6 @@ func setup(env []string) {
 		"rblf_file_exists": starlark.NewBuiltin("rblf_file_exists", fileExists),
 		// To convert find-copy-subdir and product-copy-files-by pattern
 		"rblf_find_files": starlark.NewBuiltin("rblf_find_files", find),
-		// To convert makefile's $(filter ...)/$(filter-out)
-		"rblf_regex": starlark.NewBuiltin("rblf_regex", regexMatch),
 		// To convert makefile's $(shell cmd)
 		"rblf_shell": starlark.NewBuiltin("rblf_shell", shell),
 		// Output to stderr

tools/rbcrun/host_test.go

@@ -147,10 +147,6 @@ func TestLoad(t *testing.T) {
 	}
 }
 
-func TestRegex(t *testing.T) {
-	exerciseStarlarkTestFile(t, "testdata/regex.star")
-}
-
 func TestShell(t *testing.T) {
 	if err := os.Setenv("TEST_DATA_DIR", dataDir()); err != nil {
 		t.Fatal(err)

tools/rbcrun/testdata/regex.star

@@ -1,13 +0,0 @@
-# Tests rblf_regex
-load("assert.star", "assert")
-
-
-def test():
-    pattern = "^(foo.*bar|abc.*d|1.*)$"
-    for w in ("foobar", "fooxbar", "abcxd", "123"):
-        assert.true(rblf_regex(pattern, w), "%s should match %s" % (w, pattern))
-    for w in ("afoobar", "abcde"):
-        assert.true(not rblf_regex(pattern, w), "%s should not match %s" % (w, pattern))
-
-
-test()