Merge pull request #66 from SumLare/like-implementation

strings.Like() implementation

pkg/stdlib/strings/like.go

@@ -2,12 +2,18 @@ package strings
 
 import (
 	"context"
+	"unicode"
+
 	"github.com/MontFerret/ferret/pkg/runtime/core"
 	"github.com/MontFerret/ferret/pkg/runtime/values"
 )
 
 /*
  * Checks whether the pattern search is contained in the string text, using wildcard matching.
+ * @param text (String) - The string to search in.
+ * @param search (String) - A search pattern that can contain the wildcard characters.
+ * @param caseInsensitive (Boolean) - If set to true, the matching will be case-insensitive. The default is false.
+ * @return (Boolean) - Returns true if the pattern is contained in text, and false otherwise.
  */
 func Like(_ context.Context, args ...core.Value) (core.Value, error) {
 	err := core.ValidateArgs(args, 2, 3)
@@ -16,5 +22,44 @@ func Like(_ context.Context, args ...core.Value) (core.Value, error) {
 		return values.False, err
 	}
 
-	return values.None, core.Error(core.ErrNotImplemented, "LIKE")
+	str := []rune(args[0].String())
+	pattern := []rune(args[1].String())
+
+	if len(pattern) == 0 {
+		return values.NewBoolean(len(str) == 0), nil
+	}
+
+	lookup := make([][]bool, len(str)+1)
+
+	for i := range lookup {
+		lookup[i] = make([]bool, len(pattern)+1)
+	}
+
+	lookup[0][0] = true
+
+	for j := 1; j < len(pattern)+1; j++ {
+		if pattern[j-1] == '%' {
+			lookup[0][j] = lookup[0][j-1]
+		}
+	}
+
+	for i := 1; i < len(str)+1; i++ {
+		for j := 1; j < len(pattern)+1; j++ {
+			if pattern[j-1] == '%' {
+				lookup[i][j] = lookup[i][j-1] || lookup[i-1][j]
+			} else if pattern[j-1] == '_' || str[i-1] == pattern[j-1] {
+				lookup[i][j] = lookup[i-1][j-1]
+			} else if len(args) > 2 {
+				if args[2] == values.True && unicode.ToLower(str[i-1]) == unicode.ToLower(pattern[j-1]) {
+					lookup[i][j] = lookup[i-1][j-1]
+				}
+			} else {
+				lookup[i][j] = false
+			}
+		}
+	}
+
+	matched := lookup[len(str)][len(pattern)]
+
+	return values.NewBoolean(matched), nil
 }

pkg/stdlib/strings/like_test.go

@@ -1 +1,66 @@
 package strings_test
+
+import (
+	"context"
+	"testing"
+
+	"github.com/MontFerret/ferret/pkg/runtime/values"
+	"github.com/MontFerret/ferret/pkg/stdlib/strings"
+	. "github.com/smartystreets/goconvey/convey"
+)
+
+func TestLike(t *testing.T) {
+	Convey("When args are not passed", t, func() {
+		Convey("It should return an error", func() {
+			var err error
+			_, err = strings.Like(context.Background())
+
+			So(err, ShouldBeError)
+
+			_, err = strings.Like(context.Background(), values.NewString(""))
+
+			So(err, ShouldBeError)
+		})
+	})
+
+	Convey("Should return true when matches with _ pattern", t, func() {
+		out, _ := strings.Like(
+			context.Background(),
+			values.NewString("cart"),
+			values.NewString("ca_t"),
+		)
+
+		So(out, ShouldEqual, true)
+	})
+
+	Convey("Should return true when matches with % pattern", t, func() {
+		out, _ := strings.Like(
+			context.Background(),
+			values.NewString("foo bar baz"),
+			values.NewString("%bar%"),
+		)
+
+		So(out, ShouldEqual, true)
+	})
+
+	Convey("Should return false when matches with no caseInsensitive parameter", t, func() {
+		out, _ := strings.Like(
+			context.Background(),
+			values.NewString("FoO bAr BaZ"),
+			values.NewString("fOo%bAz"),
+		)
+
+		So(out, ShouldEqual, false)
+	})
+
+	Convey("Should return true when matches with caseInsensitive parameter", t, func() {
+		out, _ := strings.Like(
+			context.Background(),
+			values.NewString("FoO bAr BaZ"),
+			values.NewString("fOo%bAz"),
+			values.True,
+		)
+
+		So(out, ShouldEqual, true)
+	})
+}