align Pratt parser error messages

jsone/prattparser.py

@@ -11,7 +11,7 @@ class SyntaxError(TemplateError):
     @classmethod
     def unexpected(cls, got, exp):
         exp = ', '.join(sorted(exp))
-        return cls('Found {}, expected {}'.format(got, exp))
+        return cls('Found {}, expected {}'.format(got.value, exp))
 
 
 Token = namedtuple('Token', ['kind', 'value', 'start', 'end'])
@@ -92,15 +92,15 @@ def parse(self, source):
         # if there are any tokens remaining, that's an error..
         token = pc.attempt()
         if token:
-            raise SyntaxError.unexpected(token.kind, self.infix_rules)
+            raise SyntaxError.unexpected(token, self.infix_rules)
         return result
 
     def parseUntilTerminator(self, source, terminator):
         pc = ParseContext(self, source, self._generate_tokens(source))
         result = pc.parse()
         token = pc.attempt()
         if token.kind != terminator:
-            raise SyntaxError.unexpected(token.kind, [terminator])
+            raise SyntaxError.unexpected(token, [terminator])
         return (result, token.start)
 
     def _generate_tokens(self, source):
@@ -167,7 +167,7 @@ def require(self, *kinds):
         if not token:
             raise SyntaxError('Unexpected end of input')
         if kinds and token.kind not in kinds:
-            raise SyntaxError.unexpected(token.kind, kinds)
+            raise SyntaxError.unexpected(token, kinds)
         return token
 
     def parse(self, precedence=None):
@@ -176,7 +176,7 @@ def parse(self, precedence=None):
         token = self.require()
         prefix_rule = parser.prefix_rules.get(token.kind)
         if not prefix_rule:
-            raise SyntaxError.unexpected(token.kind, parser.prefix_rules)
+            raise SyntaxError.unexpected(token, parser.prefix_rules)
         left = prefix_rule(parser, token, self)
         while self.next_token:
             kind = self.next_token.kind

specification.yml

@@ -1646,7 +1646,7 @@ result:   10.5
 title:    hex literal
 context:  {}
 template: {$eval: '0xff'}
-error: true
+error:    'SyntaxError: Found xff, expected !=, &&, (, *, **, +, -, ., /, <, <=, ==, >, >=, [, in, ||'
 ---
 title:    string literal with single quote
 context:  {}
@@ -1661,12 +1661,12 @@ result: 'three!'
 title:    string literal escape with backslash (not supported)
 context:  {}
 template: {$eval: '"backslash\\"maybe"'}
-error: true
+error:    'SyntaxError: Found maybe, expected !=, &&, (, *, **, +, -, ., /, <, <=, ==, >, >=, [, in, ||'
 ---
 title:    string literal escape with doubling (not supported)
 context:  {}
 template: {$eval: '"doubled""maybe"'}
-error: true
+error:    'SyntaxError: Found "maybe", expected !=, &&, (, *, **, +, -, ., /, <, <=, ==, >, >=, [, in, ||'
 ---
 title:    boolean literals
 context:  {}
@@ -1701,7 +1701,7 @@ result:   'ab'
 title:    $eval must take string
 context:  {a: 3, b: 2}
 template: {$eval: ['a', 'b']}
-error:    true
+error:    'TemplateError: expression to be evaluated must be a string'
 ---
 title: array access [index]
 context: {a: [1,2,3,4]}

src/prattparser.js

@@ -8,7 +8,10 @@ var assert = require('assert');
 var {isString} = require('./type-utils');
 var {SyntaxError, TemplateError} = require('./error');
 
-let syntaxRuleError = (token, expects) => new SyntaxError(`Found '${token.value}' expected '${expects}'`, token);
+let syntaxRuleError = (token, expects) => {
+  expects.sort();
+  return new SyntaxError(`Found ${token.value}, expected ${expects.join(', ')}`, token);
+};
 
 class PrattParser {
   constructor(options = {}) {
@@ -49,7 +52,7 @@ class PrattParser {
     let result = ctx.parse();
     let next = ctx.attempt();
     if (next) {
-      throw syntaxRuleError(next, Object.keys(this._infixRules).join(', '));
+      throw syntaxRuleError(next, Object.keys(this._infixRules));
     }
     return result;
   }
@@ -64,7 +67,7 @@ class PrattParser {
       throw new SyntaxError(`Found end of string, expected ${terminator}`,
                             {start: errorLocation, end: errorLocation});
     } else if (next.kind !== terminator) {
-      throw syntaxRuleError(next, terminator);
+      throw syntaxRuleError(next, [terminator]);
     }
     return {result, offset: next.start};
   }

test/test_prattparser.py

@@ -104,7 +104,7 @@ def fail(input, message):
             eq_(str(exc), "SyntaxError: " + message)
 
     yield fail, 'x', 'Unexpected input: \'x\''
-    yield fail, '11', 'Found number, expected *, +, -'
+    yield fail, '12', 'Found 2, expected *, +, -'
     yield fail, '(', 'Unexpected end of input'
     yield fail, '1+', 'Unexpected end of input'
     yield fail, ')', 'Found ), expected (, number'