[elpa] master 980eb3d 04/49: Support ES7 exponentiation

[Dmitry Gutov]

branch: master
commit 980eb3d92cf1b78596f58a5c5042ffc8fadb3bc4
Author: Dmitry Gutov <address@hidden>
Commit: Dmitry Gutov <address@hidden>

    Support ES7 exponentiation
    
    Closes #344
---
 NEWS.md         |    4 ++++
 js2-mode.el     |   32 +++++++++++++++++++++++++++-----
 tests/parser.el |    6 ++++++
 3 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/NEWS.md b/NEWS.md
index 87e9d72..0d69ca8 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,9 @@
 # History of user-visible changes
 
+## Next
+
+* Support for ES7 exponentiation operator.
+
 ## 2016-06-23
 
 * New variable `js2-mode-assume-strict`, for use with ES6 modules.
diff --git a/js2-mode.el b/js2-mode.el
index add73ac..6123019 100644
--- a/js2-mode.el
+++ b/js2-mode.el
@@ -539,11 +539,11 @@ which doesn't seem particularly useful, but Rhino permits 
it."
 (defvar js2-ASSIGN_MUL 98)     ; *=
 (defvar js2-ASSIGN_DIV 99)     ; /=
 (defvar js2-ASSIGN_MOD 100)    ; %=
+(defvar js2-ASSIGN_EXPON 101)
 
 (defvar js2-first-assign js2-ASSIGN)
-(defvar js2-last-assign js2-ASSIGN_MOD)
+(defvar js2-last-assign js2-ASSIGN_EXPON)
 
-(defvar js2-HOOK 101)          ; conditional (?:)
 (defvar js2-COLON 102)
 (defvar js2-OR 103)            ; logical or (||)
 (defvar js2-AND 104)           ; logical and (&&)
@@ -624,7 +624,10 @@ which doesn't seem particularly useful, but Rhino permits 
it."
 
 (defvar js2-AWAIT 169)  ; await (pseudo keyword)
 
-(defconst js2-num-tokens (1+ js2-AWAIT))
+(defvar js2-HOOK 170)          ; conditional (?:)
+(defvar js2-EXPON 171)
+
+(defconst js2-num-tokens (1+ js2-EXPON))
 
 (defconst js2-debug-print-trees nil)
 
@@ -3507,6 +3510,7 @@ The type field inherited from `js2-node' holds the 
operator."
                (cons js2-ADD "+")       ; infix plus
                (cons js2-SUB "-")       ; infix minus
                (cons js2-MUL "*")
+               (cons js2-EXPON "**")
                (cons js2-DIV "/")
                (cons js2-MOD "%")
                (cons js2-NOT "!")
@@ -3526,6 +3530,7 @@ The type field inherited from `js2-node' holds the 
operator."
                (cons js2-ASSIGN_ADD "+=")
                (cons js2-ASSIGN_SUB "-=")
                (cons js2-ASSIGN_MUL "*=")
+               (cons js2-ASSIGN_EXPON "**=")
                (cons js2-ASSIGN_DIV "/=")
                (cons js2-ASSIGN_MOD "%="))))
     (cl-loop for (k . v) in tokens do
@@ -5083,6 +5088,7 @@ You should use `js2-print-tree' instead of this function."
                       js2-ASSIGN_RSH
                       js2-ASSIGN_SUB
                       js2-ASSIGN_URSH
+                      js2-ASSIGN_EXPON
                       js2-BLOCK
                       js2-BREAK
                       js2-CALL
@@ -6194,7 +6200,11 @@ its relevant fields and puts it into `js2-ti-tokens'."
                           (?*
                            (if (js2-match-char ?=)
                                js2-ASSIGN_MUL
-                             (throw 'return js2-MUL)))
+                             (if (js2-match-char ?*)
+                                 (if (js2-match-char ?=)
+                                     js2-ASSIGN_EXPON
+                                   js2-EXPON)
+                               (throw 'return js2-MUL))))
                           (?/
                            ;; is it a // comment?
                            (when (js2-match-char ?/)
@@ -9907,7 +9917,7 @@ FIXME: The latter option is unused?"
   (list js2-MUL js2-DIV js2-MOD))
 
 (defun js2-parse-mul-expr ()
-  (let ((pn (js2-parse-unary-expr))
+  (let ((pn (js2-parse-expon-expr))
         tt
         (continue t))
     (while continue
@@ -9918,6 +9928,18 @@ FIXME: The latter option is unused?"
         (setq continue nil)))
     pn))
 
+(defun js2-parse-expon-expr ()
+  (let ((pn (js2-parse-unary-expr)))
+    (when (>= js2-language-version 200)
+      (while (js2-match-token js2-EXPON)
+        (when (and (js2-unary-node-p pn)
+                   (not (memq (js2-node-type pn) '(js2-INC js2-DEC))))
+          (js2-report-error "msg.syntax" nil
+                            (js2-node-abs-pos pn) (js2-node-len pn)))
+        ;; Make it right-associative.
+        (setq pn (js2-make-binary js2-EXPON pn 'js2-parse-expon-expr))))
+    pn))
+
 (defun js2-make-unary (type parser &rest args)
   "Make a unary node of type TYPE.
 PARSER is either a node (for postfix operators) or a function to call
diff --git a/tests/parser.el b/tests/parser.el
index b4aa683..0cd5f07 100644
--- a/tests/parser.el
+++ b/tests/parser.el
@@ -934,6 +934,12 @@ the test."
 (js2-deftest-parse parse-harmony-class-allow-semicolon-element
   "class Foo {;}" :reference "class Foo {\n}")
 
+(js2-deftest-parse exponentiation
+  "a **= b ** c ** d;")
+
+(js2-deftest-parse exponentiation-prohibits-unary-op
+  "var a = -b ** c" :syntax-error "b")
+
 ;;; Scopes
 
 (js2-deftest ast-symbol-table-includes-fn-node "function foo() {}"