Bug #8628: Parse error with method argument that is a Hash with a specific pattern

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: ruby 2.0.0p195 (2013-05-14) [i386-mingw32]
• Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN

[dimitri-lo2u (Dimitri Geshef)]

The next two lines cause a parse error

p /=/ => 'works'

/in comment/ => 'fails'

The reported error is:

syntax error, unexpected ',', expecting $end

/in comment/ => 'fails'

^

The issue is caused by the /=/ regexp in the method p call.

Notice that no parse error occurs when the Hash argument is put between parentheses

p(/=/ => 'works').

[dimitri-lo2u (Dimitri Geshef)]

First detected in ruby 1.9.3p374 (2013-01-15) [i386-mingw32]

[dimitri-lo2u (Dimitri Geshef)]

The error message when you run the snippet in attachment is:
snippet.rb:9: syntax error, unexpected tIDENTIFIER, expecting $end

/in comment/ => 'fails'

         ^

[dimitri-lo2u (Dimitri Geshef)]

Could also reproduce the problem with the regexp /,/

In other words, this will also result in a parse error:

p /,/ => 'problematic too'

/in comment/ => 'parse fails in this line'

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Rejected

p /=/' is interpreted as p /= /.../', an assignment to a variable `p'.

[dimitri-lo2u (Dimitri Geshef)]

@nobu (Nobuyoshi Nakada).
My apologies for this false alarm.
Thank you for pointing the grammatical ambiguity:
/=/ can be parsed as the /= operator followed by a regexp literal or the regexp literal /=/ itself.
Didn't realize this.