repl: implement %parse

repl/commands.go

@@ -30,6 +30,9 @@ var (
 	compileUsage = `Compile emits a textproto representation of the compiled expression.
 %compile <expr>`
 
+	parseUsage = `Parse emits a textproto representation of the parsed expression.
+%parse <expr>`
+
 	declareUsage = `Declare introduces a variable or function for type checking, but
 doesn't define a value for it:
 %declare <identifier> : <type>
@@ -86,6 +89,10 @@ type compileCmd struct {
 	expr string
 }
 
+type parseCmd struct {
+	expr string
+}
+
 type evalCmd struct {
 	expr string
 }
@@ -124,6 +131,10 @@ func (c *compileCmd) Cmd() string {
 	return "compile"
 }
 
+func (c *parseCmd) Cmd() string {
+	return "parse"
+}
+
 func (c *evalCmd) Cmd() string {
 	return "eval"
 }
@@ -186,6 +197,7 @@ func Parse(line string) (Cmder, error) {
 	if listener.cmd.Cmd() == "help" {
 		return nil, errors.New(strings.Join([]string{
 			compileUsage,
+			parseUsage,
 			declareUsage,
 			deleteUsage,
 			letUsage,
@@ -281,6 +293,10 @@ func (c *commandParseListener) EnterCompile(ctx *parser.CompileContext) {
 	c.cmd = &compileCmd{}
 }
 
+func (c *commandParseListener) EnterParse(ctx *parser.ParseContext) {
+	c.cmd = &parseCmd{}
+}
+
 func (c *commandParseListener) EnterExprCmd(ctx *parser.ExprCmdContext) {
 	c.cmd = &evalCmd{}
 }
@@ -366,6 +382,8 @@ func (c *commandParseListener) ExitExpr(ctx *parser.ExprContext) {
 	switch cmd := c.cmd.(type) {
 	case *compileCmd:
 		cmd.expr = expr
+	case *parseCmd:
+		cmd.expr = expr
 	case *evalCmd:
 		cmd.expr = expr
 	case *letFnCmd:

repl/commands_test.go

@@ -161,6 +161,9 @@ func TestParse(t *testing.T) {
 			commandLine: `%help`,
 			wantErr: errors.New(`Compile emits a textproto representation of the compiled expression.
             %compile <expr>
+
+            Parse emits a textproto representation of the parsed expression.
+            %parse <expr>
 
             Declare introduces a variable or function for type checking, but
             doesn't define a value for it:

repl/evaluator.go

@@ -950,6 +950,16 @@ func (e *Evaluator) Process(cmd Cmder) (string, bool, error) {
 			return "", false, fmt.Errorf("compile failed:\n%v", err)
 		}
 		return prototext.Format(cAST), false, nil
+	case *parseCmd:
+		ast, err := e.Parse(cmd.expr)
+		if err != nil {
+			return "", false, fmt.Errorf("parse failed:\n%v", err)
+		}
+		pAST, err := cel.AstToParsedExpr(ast)
+		if err != nil {
+			return "", false, fmt.Errorf("parse failed:\n%v", err)
+		}
+		return prototext.Format(pAST), false, nil
 	case *evalCmd:
 		val, resultT, err := e.Evaluate(cmd.expr)
 		if err != nil {
@@ -1051,3 +1061,16 @@ func (e *Evaluator) Compile(expr string) (*cel.Ast, error) {
 	}
 	return ast, nil
 }
+
+// Parse parses the input expression using the current REPL context.
+func (e *Evaluator) Parse(expr string) (*cel.Ast, error) {
+	env, _, err := e.applyContext()
+	if err != nil {
+		return nil, err
+	}
+	ast, iss := env.Parse(expr)
+	if iss.Err() != nil {
+		return nil, iss.Err()
+	}
+	return ast, nil
+}

repl/parser/Commands.g4

@@ -25,6 +25,7 @@ command: help |
          delete |
          simple |
          compile |
+         parse |
          exprCmd |
          empty;
 
@@ -48,6 +49,8 @@ empty: ;
 
 compile: '%compile' e=expr;
 
+parse: '%parse' e=expr;
+
 exprCmd: '%eval'? e=expr;
 
 qualId: leadingDot='.'? rid=IDENTIFIER ('.' qualifiers+=IDENTIFIER)*;
@@ -69,4 +72,3 @@ COMMAND: '%' IDENTIFIER;
 FLAG: '-'? '-' IDENTIFIER;
 ARROW: '->';
 EQUAL_ASSIGN: '=';
-

repl/parser/Commands.tokens

@@ -5,80 +5,82 @@ T__3=4
 T__4=5
 T__5=6
 T__6=7
-COMMAND=8
-FLAG=9
-ARROW=10
-EQUAL_ASSIGN=11
-EQUALS=12
-NOT_EQUALS=13
-IN=14
-LESS=15
-LESS_EQUALS=16
-GREATER_EQUALS=17
-GREATER=18
-LOGICAL_AND=19
-LOGICAL_OR=20
-LBRACKET=21
-RPRACKET=22
-LBRACE=23
-RBRACE=24
-LPAREN=25
-RPAREN=26
-DOT=27
-COMMA=28
-MINUS=29
-EXCLAM=30
-QUESTIONMARK=31
-COLON=32
-PLUS=33
-STAR=34
-SLASH=35
-PERCENT=36
-CEL_TRUE=37
-CEL_FALSE=38
-NUL=39
-WHITESPACE=40
-COMMENT=41
-NUM_FLOAT=42
-NUM_INT=43
-NUM_UINT=44
-STRING=45
-BYTES=46
-IDENTIFIER=47
+T__7=8
+COMMAND=9
+FLAG=10
+ARROW=11
+EQUAL_ASSIGN=12
+EQUALS=13
+NOT_EQUALS=14
+IN=15
+LESS=16
+LESS_EQUALS=17
+GREATER_EQUALS=18
+GREATER=19
+LOGICAL_AND=20
+LOGICAL_OR=21
+LBRACKET=22
+RPRACKET=23
+LBRACE=24
+RBRACE=25
+LPAREN=26
+RPAREN=27
+DOT=28
+COMMA=29
+MINUS=30
+EXCLAM=31
+QUESTIONMARK=32
+COLON=33
+PLUS=34
+STAR=35
+SLASH=36
+PERCENT=37
+CEL_TRUE=38
+CEL_FALSE=39
+NUL=40
+WHITESPACE=41
+COMMENT=42
+NUM_FLOAT=43
+NUM_INT=44
+NUM_UINT=45
+STRING=46
+BYTES=47
+IDENTIFIER=48
 '%help'=1
 '%?'=2
 '%let'=3
 '%declare'=4
 '%delete'=5
 '%compile'=6
-'%eval'=7
-'->'=10
-'='=11
-'=='=12
-'!='=13
-'in'=14
-'<'=15
-'<='=16
-'>='=17
-'>'=18
-'&&'=19
-'||'=20
-'['=21
-']'=22
-'{'=23
-'}'=24
-'('=25
-')'=26
-'.'=27
-','=28
-'-'=29
-'!'=30
-'?'=31
-':'=32
-'+'=33
-'*'=34
-'/'=35
-'%'=36
-'true'=37
-'false'=38
-'null'=39
+'%parse'=7
+'%eval'=8
+'->'=11
+'='=12
+'=='=13
+'!='=14
+'in'=15
+'<'=16
+'<='=17
+'>='=18
+'>'=19
+'&&'=20
+'||'=21
+'['=22
+']'=23
+'{'=24
+'}'=25
+'('=26
+')'=27
+'.'=28
+','=29
+'-'=30
+'!'=31
+'?'=32
+':'=33
+'+'=34
+'*'=35
+'/'=36
+'%'=37
+'true'=38
+'false'=39
+'null'=40