added regex matching for strings

compiler.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"html/template"
 	"reflect"
+	"regexp"
 
 	"github.com/gobuffalo/plush/ast"
 
@@ -379,6 +380,12 @@ func (c *compiler) stringsOperator(l string, r interface{}, op string) (interfac
 		return l <= rr, nil
 	case "==":
 		return l == rr, nil
+	case "~=":
+		x, err := regexp.Compile(rr)
+		if err != nil {
+			return nil, errors.WithStack(errors.Errorf("couldn't compile regex %s", rr))
+		}
+		return x.MatchString(l), nil
 	}
 	return nil, errors.WithStack(errors.Errorf("unknown operator for string %s", op))
 }

if_test.go

@@ -109,3 +109,11 @@ func Test_Render_If_Else_True(t *testing.T) {
 	r.NoError(err)
 	r.Equal("<p>hi</p>", s)
 }
+
+func Test_Render_If_Matches(t *testing.T) {
+	r := require.New(t)
+	input := `<p><%= if ("foo" ~= "bar") { return "hi"} else { return "bye"} %></p>`
+	s, err := Render(input, NewContext())
+	r.NoError(err)
+	r.Equal("<p>bye</p>", s)
+}

lexer/lexer.go

@@ -137,6 +137,13 @@ func (l *Lexer) nextInsideToken() token.Token {
 			break
 		}
 		tok = newToken(token.LT, l.ch)
+	case '~':
+		if l.peekChar() == '=' {
+			l.readChar()
+			tok = token.Token{Type: token.MATCHES, Literal: "~="}
+			break
+		}
+		tok = newToken(token.MATCHES, l.ch)
 	case '>':
 		if l.peekChar() == '=' {
 			l.readChar()

parser/parser.go

@@ -57,6 +57,7 @@ func newParser(l *lexer.Lexer) *parser {
 	p.registerInfix(token.ASTERISK, p.parseInfixExpression)
 	p.registerInfix(token.EQ, p.parseInfixExpression)
 	p.registerInfix(token.NOT_EQ, p.parseInfixExpression)
+	p.registerInfix(token.MATCHES, p.parseInfixExpression)
 	p.registerInfix(token.LT, p.parseInfixExpression)
 	p.registerInfix(token.GT, p.parseInfixExpression)
 	p.registerInfix(token.LTEQ, p.parseInfixExpression)

parser/parser_test.go

@@ -294,6 +294,10 @@ func Test_OperatorPrecedence(t *testing.T) {
 			"add(a * b[2], b[1], 2 * [1, 2][1])",
 			"add((a * (b[2])), (b[1]), (2 * ([1, 2][1])))",
 		},
+		{
+			"foo ~= bar",
+			"(foo ~= bar)",
+		},
 	}
 
 	for _, tt := range tests {

parser/precedences.go

@@ -17,6 +17,7 @@ const (
 var precedences = map[token.Type]int{
 	token.EQ:       EQUALS,
 	token.NOT_EQ:   EQUALS,
+	token.MATCHES:  EQUALS,
 	token.LT:       LESSGREATER,
 	token.LTEQ:     LESSGREATER,
 	token.GT:       LESSGREATER,

token/const.go

@@ -26,10 +26,11 @@ const (
 	GT   = ">"
 	GTEQ = ">="
 
-	EQ     = "=="
-	NOT_EQ = "!="
-	AND    = "&&"
-	OR     = "||"
+	EQ      = "=="
+	NOT_EQ  = "!="
+	AND     = "&&"
+	OR      = "||"
+	MATCHES = "~="
 
 	// Delimiters