Compile regexp during compilation

Author: antonmedv

eval.go

@@ -158,16 +158,6 @@ func (n binaryNode) eval(env interface{}) (interface{}, error) {
 		}
 		return !ok, nil
 
-	case "matches":
-		if isText(left) && isText(right) {
-			matched, err := regexp.MatchString(toText(right), toText(left))
-			if err != nil {
-				return nil, err
-			}
-			return matched, nil
-		}
-		return nil, fmt.Errorf("operator matches not defined on (%T, %T)", left, right)
-
 	case "~":
 		if isText(left) && isText(right) {
 			return toText(left) + toText(right), nil
@@ -255,6 +245,34 @@ func makeRange(min, max int64) ([]float64, error) {
 	return a, nil
 }
 
+func (n matchesNode) eval(env interface{}) (interface{}, error) {
+	left, err := Run(n.left, env)
+	if err != nil {
+		return nil, err
+	}
+
+	if n.r != nil {
+		if isText(left) {
+			return n.r.MatchString(toText(left)), nil
+		}
+	}
+
+	right, err := Run(n.right, env)
+	if err != nil {
+		return nil, err
+	}
+
+	if isText(left) && isText(right) {
+		matched, err := regexp.MatchString(toText(right), toText(left))
+		if err != nil {
+			return nil, err
+		}
+		return matched, nil
+	}
+
+	return nil, fmt.Errorf("operator matches doesn't defined on (%T, %T): %v", left, right, n)
+}
+
 func (n propertyNode) eval(env interface{}) (interface{}, error) {
 	v, err := Run(n.node, env)
 	if err != nil {

eval_test.go

@@ -265,6 +265,11 @@ var evalTests = []evalTest{
 		nil,
 		true,
 	},
+	{
+		`"seafood" matches "sea" ~ "food"`,
+		nil,
+		true,
+	},
 	{
 		`not ("seafood" matches "[0-9]+") ? "a" : "b"`,
 		nil,
@@ -317,7 +322,27 @@ var evalErrorTests = []evalErrorTest{
 	{
 		`"seafood" matches "a(b"`,
 		nil,
-		`error parsing regexp:`,
+		"error parsing regexp: missing closing ): `a(b`",
+	},
+	{
+		`"seafood" matches "a" ~ ")b"`,
+		nil,
+		"error parsing regexp: unexpected ): `a)b`",
+	},
+	{
+		`1 matches "1" ~ "2"`,
+		nil,
+		"operator matches doesn't defined on (float64, string): (1 matches (\"1\" ~ \"2\"))",
+	},
+	{
+		`1 matches "1"`,
+		nil,
+		"operator matches doesn't defined on (float64, string): (1 matches \"1\")",
+	},
+	{
+		`"1" matches 1`,
+		nil,
+		"operator matches doesn't defined on (string, float64): (\"1\" matches 1)",
 	},
 	{
 		`0 ? 1 : 2`,

node.go

@@ -1,5 +1,7 @@
 package expr
 
+import "regexp"
+
 // Node represents items of abstract syntax tree.
 type Node interface{}
 
@@ -36,6 +38,12 @@ type binaryNode struct {
 	right    Node
 }
 
+type matchesNode struct {
+	r     *regexp.Regexp
+	left  Node
+	right Node
+}
+
 type propertyNode struct {
 	node     Node
 	property Node

parser.go

@@ -2,6 +2,7 @@ package expr
 
 import (
 	"fmt"
+	"regexp"
 	"strconv"
 	"unicode/utf8"
 )
@@ -179,7 +180,18 @@ func (p *parser) parseExpression(precedence int) (Node, error) {
 					}
 				}
 
-				node = binaryNode{operator: token.value, left: node, right: expr}
+				if token.is(operator, "matches") {
+					var r *regexp.Regexp
+					if s, ok := expr.(textNode); ok {
+						r, err = regexp.Compile(s.value)
+						if err != nil {
+							return nil, p.errorf("%v", err)
+						}
+					}
+					node = matchesNode{r: r, left: node, right: expr}
+				} else {
+					node = binaryNode{operator: token.value, left: node, right: expr}
+				}
 				token = p.current
 				continue
 			}

parser_test.go

@@ -101,10 +101,6 @@ var parseTests = []parseTest{
 		"a ?: b",
 		conditionalNode{nameNode{"a"}, nameNode{"a"}, nameNode{"b"}},
 	},
-	{
-		`"foo" matches "/foo/"`,
-		binaryNode{"matches", textNode{"foo"}, textNode{"/foo/"}},
-	},
 	{
 		"foo.bar().foo().baz[33]",
 		propertyNode{propertyNode{methodNode{methodNode{nameNode{"foo"}, identifierNode{"bar"}, []Node{}}, identifierNode{"foo"}, []Node{}}, identifierNode{"baz"}}, numberNode{33}},
@@ -169,6 +165,10 @@ var parseErrorTests = []parseErrorTest{
 		"{-}",
 		"a map key must be a",
 	},
+	{
+		"a matches 'a)(b'",
+		"error parsing regexp: unexpected )",
+	},
 }
 
 func TestParse(t *testing.T) {
@@ -196,14 +196,42 @@ func TestParseError(t *testing.T) {
 	}
 }
 
-func TestParseErrorPosition(t *testing.T) {
-	_, err := Parse("foo() + bar(**)")
-	if err == nil {
-		err = fmt.Errorf("<nil>")
+func TestParse_matches(t *testing.T) {
+	node, err := Parse(`foo matches "foo"`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m, ok := node.(matchesNode)
+	if !ok {
+		t.Fatalf("expected to me matchesNode, got %T", node)
+	}
+
+	if !reflect.DeepEqual(m.left, nameNode{"foo"}) || !reflect.DeepEqual(m.right, textNode{"foo"}) {
+		t.Fatalf("left or right side of matches operator invalid: %#v", m)
+	}
+
+	if m.r == nil {
+		t.Fatal("regexp should be compiled")
+	}
+}
+
+func TestParse_matches_dynamic(t *testing.T) {
+	node, err := Parse(`foo matches regex`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	m, ok := node.(matchesNode)
+	if !ok {
+		t.Fatalf("expected to me matchesNode, got %T", node)
+	}
+
+	if !reflect.DeepEqual(m.left, nameNode{"foo"}) || !reflect.DeepEqual(m.right, nameNode{"regex"}) {
+		t.Fatalf("left or right side of matches operator invalid: %#v", m)
 	}
 
-	expected := "unexpected token operator(**)\nfoo() + bar(**)\n------------^"
-	if err.Error() != expected {
-		t.Errorf("\ngot\n\t%+v\nexpected\n\t%v", err.Error(), expected)
+	if m.r != nil {
+		t.Fatal("regexp should not be compiled")
 	}
 }

print.go

@@ -44,6 +44,10 @@ func (n binaryNode) String() string {
 	return fmt.Sprintf("(%v %v %v)", n.left, n.operator, n.right)
 }
 
+func (n matchesNode) String() string {
+	return fmt.Sprintf("(%v matches %v)", n.left, n.right)
+}
+
 func (n propertyNode) String() string {
 	switch n.property.(type) {
 	case identifierNode:

print_test.go

@@ -43,6 +43,14 @@ var printTests = []printTest{
 		binaryNode{"and", binaryNode{"or", nameNode{"a"}, nameNode{"b"}}, nameNode{"c"}},
 		"((a or b) and c)",
 	},
+	{
+		matchesNode{left: nameNode{"foo"}, right: textNode{"foobar"}},
+		"(foo matches \"foobar\")",
+	},
+	{
+		conditionalNode{nameNode{"a"}, nameNode{"a"}, nameNode{"b"}},
+		"a ? a : b",
+	},
 }
 
 func TestPrint(t *testing.T) {