Move generics to own package

expressions/expressions.y

@@ -3,9 +3,12 @@ package expressions
 import (
     "fmt"
 	"reflect"
+	"github.com/osteele/liquid/generics"
 )
 
 func init() {
+	// This allows adding and removing references to fmt in the rules below,
+	// without having to edit the import statement to avoid erorrs each time.
 	_ = fmt.Sprint("")
 }
 
@@ -79,25 +82,24 @@ expr1:
 rel:
   expr1
 | expr EQ expr {
-	a, b := $1, $3
+	fa, fb := $1, $3
 	$$ = func(ctx Context) interface{} {
-		aref, bref := reflect.ValueOf(a(ctx)), reflect.ValueOf(b(ctx))
-		return GenericCompare(aref, bref) == 0
+		a, b := fa(ctx), fb(ctx)
+		return generics.Equal(a, b)
 	}
 }
 | expr '<' expr {
-	a, b := $1, $3
+	fa, fb := $1, $3
 	$$ = func(ctx Context) interface{} {
-		aref, bref := reflect.ValueOf(a(ctx)), reflect.ValueOf(b(ctx))
-		return GenericCompare(aref, bref) < 0
+		a, b := fa(ctx), fb(ctx)
+		return generics.Less(a, b)
 	}
 }
 | expr '>' expr {
-	a, b := $1, $3
+	fa, fb := $1, $3
 	$$ = func(ctx Context) interface{} {
-		aref, bref := reflect.ValueOf(a(ctx)), reflect.ValueOf(b(ctx))
-		return GenericCompare(aref, bref) > 0
+		a, b := fa(ctx), fb(ctx)
+		return generics.Less(b, a)
 	}
 }
 ;
-

expressions/filters.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"github.com/osteele/liquid/errors"
+	"github.com/osteele/liquid/generics"
 )
 
 type InterpreterError string
@@ -33,9 +34,9 @@ func sortFilter(in []interface{}, key interface{}) []interface{} {
 		out[i] = v
 	}
 	if key == nil {
-		genericSort(out)
+		generics.Sort(out)
 	} else {
-		sortByProperty(out, key.(string))
+		generics.SortByProperty(out, key.(string))
 	}
 	return out
 }
@@ -87,7 +88,7 @@ func makeFilter(f valueFn, name string, param valueFn) valueFn {
 		defer func() {
 			if r := recover(); r != nil {
 				switch e := r.(type) {
-				case genericError:
+				case generics.GenericError:
 					panic(InterpreterError(e.Error()))
 				default:
 					// fmt.Println(string(debug.Stack()))
@@ -99,7 +100,7 @@ func makeFilter(f valueFn, name string, param valueFn) valueFn {
 		if param != nil {
 			args = append(args, param(ctx))
 		}
-		out, err := genericApply(fr, args)
+		out, err := generics.Apply(fr, args)
 		if err != nil {
 			panic(err)
 		}