Fix #292 Error poco claro cuando se omite el receptor de un mensaje

src/parser.ts

@@ -1,5 +1,5 @@
 import { log } from 'console'
-import Parsimmon, { alt as alt_parser, any, Index, index, lazy, makeSuccess, newline, notFollowedBy, of, Parser, regex, seq, seqObj, string, whitespace } from 'parsimmon'
+import Parsimmon, { alt as alt_parser, any, Index, index, lazy, makeSuccess, newline, notFollowedBy, of, Parser, regex, seq, seqObj, string, succeed, whitespace } from 'parsimmon'
 import unraw from 'unraw'
 import { ASSIGNATION_OPERATORS, INFIX_OPERATORS, KEYWORDS, LIST_MODULE, PREFIX_OPERATORS, SET_MODULE } from './constants'
 import { discriminate, hasWhitespace, is, List, mapObject } from './extensions'
@@ -19,6 +19,7 @@
 export const MALFORMED_ENTITY = 'malformedEntity'
 export const MALFORMED_MEMBER = 'malformedMember'
 export const MALFORMED_SENTENCE = 'malformedSentence'
+export const MALFORMED_MESSAGE_SEND = 'malformedMessageSend'
 
 export class ParseError implements BaseProblem {
   constructor(public code: Name, public sourceMap: SourceMap) { }
@@ -103,6 +104,11 @@
 const comment = (position: 'start' | 'end' | 'inner') => lazy('comment', () => regex(/\/\*(.|[\r\n])*?\*\/|\/\/.*/)).map(text => new Annotation('comment', { text, position }))
 const sameLineComment: Parser<Annotation> = spaces.then(comment('end'))
 
+const withSameLineComment = <T extends Node>(result: T): Parser<T> => 
+  optional(sameLineComment).map(comment => comment
+      ? result.copy({ metadata: result.metadata.concat(comment) })
+      : result)
+
 export const sanitizeWhitespaces = (originalFrom: SourceIndex, originalTo: SourceIndex, input: string): [SourceIndex, SourceIndex] => {
   const EOL = input.includes('\r\n') ? '\r\n' : '\n'
   const hasLineBreaks = (aString: string) => aString.includes(EOL)
@@ -227,7 +233,8 @@
     sentences: alt(
       Sentence.skip(__),
       comment('inner').wrap(_, _),
-      sentenceError).many(),
+      sentenceError
+    ).many(),
   }).wrap(key('{'), lastKey('}')).map(recover)
 )
 
@@ -452,12 +459,35 @@
 
 const postfixMessageChain: Parser<ExpressionNode> = lazy(() =>
   messageChain(
-    primaryExpression,
+    postfixMessageChainInitialReceiver,
     key('.').then(name),
     alt(unamedArguments, Closure.times(1))
   )
 )
 
+const postfixMessageChainInitialReceiver: Parser<ExpressionNode & { problems?: List<BaseProblem> }> = lazy(() => 
+  alt(
+    primaryExpression,
+    obj({
+      markedMessage: name.mark(),
+      args: alt(unamedArguments, Closure.times(1)),
+    }).mark().chain(({
+      start,
+      end,
+      value: { 
+        markedMessage: { value: message, start: errorStart, end: errorEnd }, 
+        args 
+      },
+    }) => Parsimmon((input: string, i: number) => makeSuccess(i, new SendNode({
+      receiver: new LiteralNode({ value: null }),
+      message, 
+      args,
+      problems: [new ParseError(MALFORMED_MESSAGE_SEND, buildSourceMap(errorStart, errorEnd))],
+      sourceMap: buildSourceMap(...sanitizeWhitespaces(start, end, input))
+    }))))
+  ).chain(withSameLineComment)
+)
+
 const messageChain = (receiver: Parser<ExpressionNode>, message: Parser<Name>, args: Parser<List<ExpressionNode>>): Parser<ExpressionNode> => lazy(() =>
   seq(
     index,
@@ -498,7 +528,6 @@
   )
 })
 
-
 export const Self: Parser<SelfNode> = node(SelfNode)(() =>
   key(KEYWORDS.SELF).result({})
 )

test/parser.test.ts

@@ -45,6 +45,17 @@ describe('Wollok parser', () => {
         }))
     })
 
+    it('comments after malformed sends should be parsed', () => {
+      'vola() //some comment'
+      .should.be.parsedBy(parse.Send)
+      .recoveringFrom(parse.MALFORMED_MESSAGE_SEND, 0, 4)
+        .into(new Send({
+          receiver: new Literal({ value: null }),
+          message: 'vola',
+          metadata: [new Annotation('comment', { text: '//some comment', position: 'end' })],
+        }))
+    })
+
     it('comments after variable should be parsed', () => {
       'const a = 1 //some comment'
         .should.be.parsedBy(parse.Variable).into(new Variable({
@@ -2723,16 +2734,66 @@ class c {}`
           'a.'.should.not.be.parsedBy(parser)
         })
 
-        it('should not parse a call to a method without the reference that is calling', () => {
-          'm(p,q)'.should.not.be.parsedBy(parser)
-        })
-
         it('should not parse an expression with a "." at the start', () => {
           '.m'.should.not.be.parsedBy(parser)
         })
 
-      })
+        it('should recover from malformed message send without arguments', () => {
+          `m()`.should.be.parsedBy(parser)
+            .recoveringFrom(parse.MALFORMED_MESSAGE_SEND, 0, 1)
+            .into(new Send({ 
+              receiver: new Literal({ value: null }),
+              message: 'm',
+              args: [],
+            }))
+        })
+
+        it('should recover from malformed message send with one argument', () => {
+          `m(p)`.should.be.parsedBy(parser)
+            .recoveringFrom(parse.MALFORMED_MESSAGE_SEND, 0, 1)
+            .into(new Send({ 
+              receiver: new Literal({ value: null }),
+              message: 'm',
+              args: [ new Reference({ name: 'p' }) ],
+            }))
+        })
+
+        it('should recover from malformed message send with multiple arguments', () => {
+          'm(p,q)'.should.be.parsedBy(parser)
+            .recoveringFrom(parse.MALFORMED_MESSAGE_SEND, 0, 1)
+            .into(new Send({ 
+              receiver: new Literal({ value: null }),
+              message: 'm',
+              args: [
+                new Reference({ name: 'p' }),
+                new Reference({ name: 'q' })
+              ],
+            }))
+        })
 
+        it('should parse malformed message sends with a closure as an argument', () => {
+          'm1 {p => p}'.should.be.parsedBy(parser)
+            .recoveringFrom(parse.MALFORMED_MESSAGE_SEND, 0, 2)
+            .into(
+              new Send({
+                receiver: new Literal({ value: null }),
+                message: 'm1',
+                args: [
+                  Closure({
+                    parameters: [new Parameter({ name: 'p' })],
+                    sentences: [new Return({ value: new Reference({ name: 'p' }) })],
+                    code: '{p => p}',
+                  }),
+                ],
+              })
+            )
+            .and.exist.tracedTo(0,11)
+            .and.have.nested.property('args.0').tracedTo(3, 11)
+            .and.also.have.nested.property('args.0.members.0.parameters.0').tracedTo(4, 5)
+            .and.also.have.nested.property('args.0.members.0.body.sentences.0.value').tracedTo(9, 10)
+        })
+
+      })
 
       describe('New', () => {