code review 5795073: text/template: fix a couple of parse bugs around identi...

text/template: fix a couple of parse bugs around identifiers.
1) Poor error checking in variable declarations admitted
$x=2 or even $x%2.
2) Need white space or suitable termination character
after identifiers, so $x+2 doesn't parse, in case we want it
to mean something one day.
Number 2 in particular prevents mistakes that we will have
to honor later and so is necessary for Go 1.

Fixes issue 3270.
Fixes issue 3271.

[r, 2012-03-13 06:42:58]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[rsc, 2012-03-13 13:18:22]

LGTM

bug1c, while valid to parse, is not valid to execute,
and text/template does not diagnose this.

Example: http://play.golang.org/p/PI6OeJL-BK

[r, 2012-03-13 20:03:17]

*** Submitted as http://code.google.com/p/go/source/detail?r=fdd527534db9 ***

text/template: fix a couple of parse bugs around identifiers.
1) Poor error checking in variable declarations admitted
$x=2 or even $x%2.
2) Need white space or suitable termination character
after identifiers, so $x+2 doesn't parse, in case we want it
to mean something one day.
Number 2 in particular prevents mistakes that we will have
to honor later and so is necessary for Go 1.

Fixes issue 3270.
Fixes issue 3271.

R=golang-dev, rsc
CC=golang-dev
http://codereview.appspot.com/5795073