[elpa] 07/46: Cut down on reserved words; improve error reporting

[Dmitry Gutov]

dgutov pushed a commit to branch master
in repository elpa.

commit 0815f85d5460242febe06756abfb209fad4aa701
Author: Dmitry Gutov <address@hidden>
Date:   Sun Apr 6 06:26:54 2014 +0300

    Cut down on reserved words; improve error reporting
    
    Closes #100
---
 js2-mode.el     |   58 +++++++++++++++++++++++++-----------------------------
 tests/parser.el |    6 ++--
 2 files changed, 30 insertions(+), 34 deletions(-)

diff --git a/js2-mode.el b/js2-mode.el
index da9aab9..2b3af58 100644
--- a/js2-mode.el
+++ b/js2-mode.el
@@ -1649,7 +1649,7 @@ the correct number of ARGS must be provided."
          "missing ) in parenthetical")
 
 (js2-msg "msg.reserved.id"
-         "identifier is a reserved word")
+         "'%s' is a reserved identifier")
 
 (js2-msg "msg.no.paren.catch"
          "missing ( before catch-block condition")
@@ -1907,10 +1907,6 @@ the correct number of ARGS must be provided."
          "illegal octal literal digit %s; "
          "interpreting it as a decimal digit")
 
-(js2-msg "msg.reserved.keyword"
-         "illegal usage of future reserved keyword %s; "
-         "interpreting it as ordinary identifier")
-
 (js2-msg "msg.script.is.not.constructor"
          "Script objects are not constructors.")
 
@@ -5284,21 +5280,10 @@ into temp buffers."
   "Vector whose values are non-nil for tokens that are keywords.
 The values are default faces to use for highlighting the keywords.")
 
-(defconst js2-reserved-words
-  '(abstract
-    boolean byte
-    char class
-    double
-    enum export extends
-    final float
-    goto
-    implements import int interface
-    long
-    native
-    package private protected public
-    short static super synchronized
-    throws transient
-    volatile))
+;; FIXME: Support strict mode-only future reserved words, after we know
+;; which parts scopes are in strict mode, and which are not.
+(defconst js2-reserved-words '(class export extends import super)
+  "Future reserved keywords in ECMAScript 5.")
 
 (defconst js2-keyword-names
   (let ((table (make-hash-table :test 'equal)))
@@ -5521,9 +5506,9 @@ its relevant fields and puts it into `js2-ti-tokens'."
                        (memq result '(js2-LET js2-YIELD)))
                   ;; LET and YIELD are tokens only in 1.7 and later
                   (setq result 'js2-NAME))
-              (if (not (eq result 'js2-RESERVED))
-                  (throw 'return (js2-tt-code result)))
-              (js2-report-warning "msg.reserved.keyword" str)))
+              (when (eq result 'js2-RESERVED)
+                (setf (js2-token-string token) str))
+              (throw 'return (js2-tt-code result))))
           ;; If we want to intern these as Rhino does, just use (intern str)
           (setf (js2-token-string token) str)
           (throw 'return js2-NAME))     ; end identifier/kwd check
@@ -7024,11 +7009,11 @@ from `js2-ti-tokens'.  Otherwise, call `js2-get-token'."
 
 (defalias 'js2-next-token 'js2-get-token)
 
-(defun js2-match-token (match)
+(defun js2-match-token (match &optional dont-unget)
   "Get next token and return t if it matches MATCH, a bytecode.
 Returns nil and consumes nothing if MATCH is not the next token."
   (if (/= (js2-get-token) match)
-      (ignore (js2-unget-token))
+      (ignore (unless dont-unget (js2-unget-token)))
     t))
 
 (defun js2-match-contextual-kwd (name)
@@ -7046,7 +7031,8 @@ string is NAME.  Returns nil and keeps current token 
otherwise."
   (or (= tt js2-NAME)
       (and js2-allow-keywords-as-property-names
            (plusp tt)
-           (aref js2-kwd-tokens tt))))
+           (or (= tt js2-RESERVED)
+               (aref js2-kwd-tokens tt)))))
 
 (defun js2-match-prop-name ()
   "Consume token and return t if next token is a valid property name.
@@ -7080,9 +7066,19 @@ same line as its operand."
   "Match next token to token code TOKEN, or record a syntax error.
 MSG-ID is the error message to report if the match fails.
 Returns t on match, nil if no match."
-  (if (js2-match-token token)
+  (if (js2-match-token token t)
       t
     (js2-report-error msg-id nil pos len)
+    (js2-unget-token)
+    nil))
+
+(defun js2-must-match-name (msg-id)
+  (if (js2-match-token js2-NAME t)
+      t
+    (if (eq (js2-current-token-type) js2-RESERVED)
+        (js2-report-error "msg.reserved.id" (js2-current-token-string))
+      (js2-report-error msg-id)
+      (js2-unget-token))
     nil))
 
 (defsubst js2-inside-function ()
@@ -7343,7 +7339,7 @@ NODE is either `js2-array-node', `js2-object-node', or 
`js2-name-node'."
                          (not rest-param-at))
                 ;; to report errors if there are more parameters
                 (setq rest-param-at (length params)))
-              (js2-must-match js2-NAME "msg.no.parm")
+              (js2-must-match-name "msg.no.parm")
               (js2-record-face 'js2-function-param)
               (setq param (js2-create-name-node))
               (js2-define-symbol js2-LP (js2-current-token-string) param)
@@ -7404,7 +7400,7 @@ Last token scanned is the close-curly for the function 
body."
 (defun js2-parse-function-stmt ()
   (let ((pos (js2-current-token-beg))
         (star-p (js2-match-token js2-MUL)))
-    (js2-must-match js2-NAME "msg.unnamed.function.stmt")
+    (js2-must-match-name "msg.unnamed.function.stmt")
     (let ((name (js2-create-name-node t))
           pn member-expr)
       (cond
@@ -7914,7 +7910,7 @@ Parses for, for-in, and for each-in statements."
             (js2-define-destruct-symbols param js2-LET nil))
            ;; simple name
            (t
-            (js2-must-match js2-NAME "msg.bad.catchcond")
+            (js2-must-match-name "msg.bad.catchcond")
             (setq param (js2-create-name-node))
             (js2-define-symbol js2-LET (js2-current-token-string) param))))
         ;; pattern guard
@@ -8352,7 +8348,7 @@ Returns the parsed `js2-var-decl-node' expression node."
                 end (js2-node-end destructuring))
         ;; Simple variable name
         (js2-unget-token)
-        (when (js2-must-match js2-NAME "msg.bad.var")
+        (when (js2-must-match-name "msg.bad.var")
           (setq name (js2-create-name-node)
                 nbeg (js2-current-token-beg)
                 nend (js2-current-token-end)
diff --git a/tests/parser.el b/tests/parser.el
index 60634bb..1da9108 100644
--- a/tests/parser.el
+++ b/tests/parser.el
@@ -97,7 +97,7 @@ the test."
   "function foo() {\n}")
 
 (js2-deftest-parse function-expression-statements-are-verboten
-  "function() {}" :syntax-error "function")
+  "function() {}" :syntax-error "(")
 
 (js2-deftest-parse member-expr-as-function-name
   "function a.b.c[2](x, y) {\n}"
@@ -199,10 +199,10 @@ the test."
   "(a, b = 1, ...c) => {  c;\n};")
 
 (js2-deftest-parse parenless-arrow-function-prohibits-rest
-  "...b => {b + 1;};" :syntax-error "b" :errors-count 2)
+  "...b => {b + 1;};" :syntax-error "=>" :errors-count 2)
 
 (js2-deftest-parse parenless-arrow-function-prohibits-destructuring
-  "[a, b] => {a + b;};" :syntax-error "]" :errors-count 5)
+  "[a, b] => {a + b;};" :syntax-error "=>" :errors-count 5)
 
 ;;; Automatic semicolon insertion