Added support of using keywords in namespaces (#481)

* Added support of using keywords in namespaces

* Added true and false

* Removed unnecessary string case

.gitignore

@@ -133,4 +133,5 @@ dist
 coverage.txt
 
 # sometimes antlr generates stub
-**/.antlr
+**/.antlr
+gen

pkg/compiler/compiler_func_ns_test.go

@@ -2,6 +2,7 @@ package compiler_test
 
 import (
 	"context"
+	"fmt"
 	"github.com/MontFerret/ferret/pkg/compiler"
 	"github.com/MontFerret/ferret/pkg/runtime/core"
 	"github.com/MontFerret/ferret/pkg/runtime/values"
@@ -78,4 +79,74 @@ func TestFunctionNSCall(t *testing.T) {
 
 		So(err, ShouldNotBeNil)
 	})
+
+	Convey("Should use keywords", t, func() {
+		c := compiler.New()
+
+		keywords := []string{
+			"And",
+			"Or",
+			"For",
+			"Return",
+			"Distinct",
+			"Filter",
+			"Sort",
+			"Limit",
+			"Let",
+			"Collect",
+			"Desc",
+			"Asc",
+			"None",
+			"Null",
+			"True",
+			"False",
+			"Use",
+			"Into",
+			"Keep",
+			"With",
+			"Count",
+			"All",
+			"Any",
+			"Aggregate",
+			"Like",
+			"Not",
+			"In",
+		}
+
+		for _, kw := range keywords {
+			segment := kw
+			err := c.Namespace("T").Namespace(segment).RegisterFunction("TEST", func(ctx context.Context, args ...core.Value) (core.Value, error) {
+				return values.True, nil
+			})
+
+			So(err, ShouldBeNil)
+
+			err = c.Namespace("T").Namespace(segment).RegisterFunction(segment, func(ctx context.Context, args ...core.Value) (core.Value, error) {
+				return values.True, nil
+			})
+
+			So(err, ShouldBeNil)
+
+			p, err := c.Compile(fmt.Sprintf(`
+			RETURN T::%s::TEST()
+		`, segment))
+
+			So(err, ShouldBeNil)
+
+			out := p.MustRun(context.Background())
+
+			So(string(out), ShouldEqual, "true")
+
+			p, err = c.Compile(fmt.Sprintf(`
+			RETURN T::%s::%s()
+		`, segment, segment))
+
+			So(err, ShouldBeNil)
+
+			out = p.MustRun(context.Background())
+
+			So(string(out), ShouldEqual, "true")
+		}
+	})
+
 }

pkg/compiler/visitor.go

@@ -1171,7 +1171,7 @@ func (v *visitor) doVisitFunctionCallExpression(context *fql.FunctionCallExpress
 		name += funcNS.GetText()
 	}
 
-	name += context.Identifier().GetText()
+	name += context.FunctionIdentifier().GetText()
 
 	fun, exists := v.funcs.Get(name)
 

pkg/parser/antlr/FqlLexer.tokens

@@ -44,22 +44,23 @@ SortDirection=43
 None=44
 Null=45
 BooleanLiteral=46
-Into=47
-Keep=48
-With=49
-Count=50
-All=51
-Any=52
-Aggregate=53
-Like=54
-Not=55
-In=56
-Param=57
-Identifier=58
-StringLiteral=59
-IntegerLiteral=60
-FloatLiteral=61
-NamespaceSegment=62
+Use=47
+Into=48
+Keep=49
+With=50
+Count=51
+All=52
+Any=53
+Aggregate=54
+Like=55
+Not=56
+In=57
+Param=58
+Identifier=59
+StringLiteral=60
+IntegerLiteral=61
+FloatLiteral=62
+NamespaceSegment=63
 ':'=5
 ';'=6
 '.'=7
@@ -97,13 +98,14 @@ NamespaceSegment=62
 'COLLECT'=42
 'NONE'=44
 'NULL'=45
-'INTO'=47
-'KEEP'=48
-'WITH'=49
-'COUNT'=50
-'ALL'=51
-'ANY'=52
-'AGGREGATE'=53
-'LIKE'=54
-'IN'=56
-'@'=57
+'USE'=47
+'INTO'=48
+'KEEP'=49
+'WITH'=50
+'COUNT'=51
+'ALL'=52
+'ANY'=53
+'AGGREGATE'=54
+'LIKE'=55
+'IN'=57
+'@'=58

pkg/parser/antlr/FqlParser.g4

@@ -223,8 +223,37 @@ namespace
     : (NamespaceSegment)*
     ;
 
+functionIdentifier
+    : Identifier
+    | And
+    | Or
+    | For
+    | Return
+    | Distinct
+    | Filter
+    | Sort
+    | Limit
+    | Let
+    | Collect
+    | SortDirection
+    | None
+    | Null
+    | BooleanLiteral
+    | Use
+    | Into
+    | Keep
+    | With
+    | Count
+    | All
+    | Any
+    | Aggregate
+    | Like
+    | Not
+    | In
+    ;
+
 functionCallExpression
-    : namespace Identifier arguments
+    : namespace functionIdentifier arguments
     ;
 
 member

pkg/parser/fql/fqlparser_base_listener.go

@@ -304,6 +304,12 @@ func (s *BaseFqlParserListener) EnterNamespace(ctx *NamespaceContext) {}
 // ExitNamespace is called when production namespace is exited.
 func (s *BaseFqlParserListener) ExitNamespace(ctx *NamespaceContext) {}
 
+// EnterFunctionIdentifier is called when production functionIdentifier is entered.
+func (s *BaseFqlParserListener) EnterFunctionIdentifier(ctx *FunctionIdentifierContext) {}
+
+// ExitFunctionIdentifier is called when production functionIdentifier is exited.
+func (s *BaseFqlParserListener) ExitFunctionIdentifier(ctx *FunctionIdentifierContext) {}
+
 // EnterFunctionCallExpression is called when production functionCallExpression is entered.
 func (s *BaseFqlParserListener) EnterFunctionCallExpression(ctx *FunctionCallExpressionContext) {}
 

pkg/parser/fql/fqlparser_base_visitor.go

@@ -195,6 +195,10 @@ func (v *BaseFqlParserVisitor) VisitNamespace(ctx *NamespaceContext) interface{}
 	return v.VisitChildren(ctx)
 }
 
+func (v *BaseFqlParserVisitor) VisitFunctionIdentifier(ctx *FunctionIdentifierContext) interface{} {
+	return v.VisitChildren(ctx)
+}
+
 func (v *BaseFqlParserVisitor) VisitFunctionCallExpression(ctx *FunctionCallExpressionContext) interface{} {
 	return v.VisitChildren(ctx)
 }

pkg/parser/fql/fqlparser_listener.go

@@ -148,6 +148,9 @@ type FqlParserListener interface {
 	// EnterNamespace is called when entering the namespace production.
 	EnterNamespace(c *NamespaceContext)
 
+	// EnterFunctionIdentifier is called when entering the functionIdentifier production.
+	EnterFunctionIdentifier(c *FunctionIdentifierContext)
+
 	// EnterFunctionCallExpression is called when entering the functionCallExpression production.
 	EnterFunctionCallExpression(c *FunctionCallExpressionContext)
 
@@ -337,6 +340,9 @@ type FqlParserListener interface {
 	// ExitNamespace is called when exiting the namespace production.
 	ExitNamespace(c *NamespaceContext)
 
+	// ExitFunctionIdentifier is called when exiting the functionIdentifier production.
+	ExitFunctionIdentifier(c *FunctionIdentifierContext)
+
 	// ExitFunctionCallExpression is called when exiting the functionCallExpression production.
 	ExitFunctionCallExpression(c *FunctionCallExpressionContext)
 

pkg/parser/fql/fqlparser_visitor.go

@@ -148,6 +148,9 @@ type FqlParserVisitor interface {
 	// Visit a parse tree produced by FqlParser#namespace.
 	VisitNamespace(ctx *NamespaceContext) interface{}
 
+	// Visit a parse tree produced by FqlParser#functionIdentifier.
+	VisitFunctionIdentifier(ctx *FunctionIdentifierContext) interface{}
+
 	// Visit a parse tree produced by FqlParser#functionCallExpression.
 	VisitFunctionCallExpression(ctx *FunctionCallExpressionContext) interface{}