Implement multiline comments and be more forgiving of extra whitespace

packages/js/expression-evaluation/src/parser.ts

@@ -104,16 +104,22 @@ LineTerminatorSequence
 	/ "\\u2028"
 	/ "\\u2029"
 
+Comment "comment"
+	= MultiLineComment
+
+MultiLineComment
+	= "/*" (!"*/" SourceCharacter)* "*/"
+
 __ "skipped"
-	= (WhiteSpace / LineTerminatorSequence )*
+	= (WhiteSpace / LineTerminatorSequence / Comment)*
 
 IdentifierPath
-	= variable:Identifier accessor:("." Identifier)* {
+	= variable:Identifier accessor:(__ "." __ Identifier)* {
 		const path = variable.split( '.' );
 		let result = path.reduce( ( nextObject, propertyName ) => nextObject[ propertyName ], options.context );
 
 		for ( let i = 0; i < accessor.length; i++ ) {
-			result = result[ accessor[ i ][ 1 ] ];
+			result = result[ accessor[ i ][ 3 ] ];
 		}
 
 		return result;
@@ -378,7 +384,9 @@ LogicalOrOperator
 	= "||"
 
 Expression
-	= LogicalOrExpression
+	= __ expression:LogicalOrExpression __ {
+		return expression;
+	}
 `;
 
 export const parser = peggy.generate( grammar );

packages/js/expression-evaluation/src/test/index.test.ts

@@ -116,6 +116,12 @@ describe( 'evaluate', () => {
 		expect( result ).toEqual( "foo \\'bar\\'" );
 	} );
 
+	it( 'should evaluate a literal with whitespace around it', () => {
+		const result = evaluate( ' 23 ' );
+
+		expect( result ).toEqual( 23 );
+	} );
+
 	it( 'should evaluate a top-level context property', () => {
 		const result = evaluate( 'foo', {
 			foo: 'bar',
@@ -124,6 +130,14 @@ describe( 'evaluate', () => {
 		expect( result ).toEqual( 'bar' );
 	} );
 
+	it( 'should evaluate a top-level context property with whitespace', () => {
+		const result = evaluate( ' foo ', {
+			foo: 'bar',
+		} );
+
+		expect( result ).toEqual( 'bar' );
+	} );
+
 	it( 'should evaluate a nested context property', () => {
 		const result = evaluate( 'foo.bar', {
 			foo: {
@@ -134,6 +148,30 @@ describe( 'evaluate', () => {
 		expect( result ).toEqual( 'baz' );
 	} );
 
+	it( 'should evaluate a nested context property with whitespace', () => {
+		const result = evaluate( 'foo. bar', {
+			foo: {
+				bar: 'baz',
+			},
+		} );
+
+		expect( result ).toEqual( 'baz' );
+	} );
+
+	it( 'should evaluate a nested context property with multiple lines', () => {
+		const result = evaluate(
+			`foo.
+			bar`,
+			{
+				foo: {
+					bar: 'baz',
+				},
+			}
+		);
+
+		expect( result ).toEqual( 'baz' );
+	} );
+
 	it( 'should evaluate a NOT expression', () => {
 		const result = evaluate( '!foo', {
 			foo: true,
@@ -158,6 +196,14 @@ describe( 'evaluate', () => {
 		expect( result ).toEqual( false );
 	} );
 
+	it( 'should evaluate a NOT expression with parentheses and spaces', () => {
+		const result = evaluate( '! ( foo ) ', {
+			foo: true,
+		} );
+
+		expect( result ).toEqual( false );
+	} );
+
 	it( 'should evaluate a multiplication expression', () => {
 		const result = evaluate( 'foo * 2', {
 			foo: 2,
@@ -351,6 +397,50 @@ describe( 'evaluate', () => {
 		expect( result ).toEqual( true );
 	} );
 
+	it( 'should evaluate an expression with a multiline comment at the end', () => {
+		const result = evaluate( 'foo /* + 23 */', {
+			foo: 5,
+		} );
+
+		expect( result ).toEqual( 5 );
+	} );
+
+	it( 'should evaluate an expression with a multiline comment at the beginning', () => {
+		const result = evaluate( '/* 23 + */ foo', {
+			foo: 5,
+		} );
+
+		expect( result ).toEqual( 5 );
+	} );
+
+	it( 'should evaluate an expression with a multiline comment in the middle', () => {
+		const result = evaluate( 'foo + /* 23 */ bar', {
+			foo: 5,
+			bar: 3,
+		} );
+
+		expect( result ).toEqual( 8 );
+	} );
+
+	it( 'should evaluate a multiline expression with a multiline comment', () => {
+		const result = evaluate(
+			`foo
+			/*
+			+ bar
+			+ boo
+			*/
+			+ baz`,
+			{
+				foo: 5,
+				bar: 23,
+				boo: 6,
+				baz: 3,
+			}
+		);
+
+		expect( result ).toEqual( 8 );
+	} );
+
 	it( 'should throw an error if the expression is invalid', () => {
 		expect( () => evaluate( '= 1' ) ).toThrow();
 	} );