[ruby-core:105610] [Ruby master Feature#18242] Parser makes multiple assignment sad in confusing way
From:
"danh337 (Dan H)" <noreply@...>
Date:
2021-10-09 02:40:09 UTC
List:
ruby-core #105610
Issue #18242 has been updated by danh337 (Dan H). File driver.rb added Attached is an improved driver. Again, every test case works with nobu's branch. ---------------------------------------- Feature #18242: Parser makes multiple assignment sad in confusing way https://bugs.ruby-lang.org/issues/18242#change-94098 * Author: danh337 (Dan H) * Status: Open * Priority: Normal ---------------------------------------- Example: ``` ruby a, b = 2, 1 if 1 < 2 # Works a, b = [2, 1] if 1 < 2 # Works (a, b) = 2, 1 if 1 < 2 # Works (a, b) = [2, 1] if 1 < 2 # Works (a, b = [2, 1]) if 1 < 2 # Works a, b = 2, 1 unless 2 < 1 # Works a, b = [2, 1] unless 2 < 1 # Works (a, b) = 2, 1 unless 2 < 1 # Works (a, b) = [2, 1] unless 2 < 1 # Works (a, b = [2, 1]) unless 2 < 1 # Works 1 < 2 and a, b = 2, 1 # SyntaxError 1 < 2 and a, b = [2, 1] # SyntaxError 1 < 2 and (a, b) = 2, 1 # SyntaxError 1 < 2 and (a, b) = [2, 1] # SyntaxError (1 < 2) and a, b = 2, 1 # SyntaxError (1 < 2) and a, b = [2, 1] # SyntaxError (1 < 2) and (a, b) = 2, 1 # SyntaxError (1 < 2) and (a, b) = [2, 1] # SyntaxError 1 < 2 and (a, b = 2, 1) # Works 1 < 2 and (a, b = [2, 1]) # Works 2 < 1 or a, b = 2, 1 # SyntaxError 2 < 1 or a, b = [2, 1] # SyntaxError 2 < 1 or (a, b) = 2, 1 # SyntaxError 2 < 1 or (a, b) = [2, 1] # SyntaxError (2 < 1) or a, b = 2, 1 # SyntaxError (2 < 1) or a, b = [2, 1] # SyntaxError (2 < 1) or (a, b) = 2, 1 # SyntaxError (2 < 1) or (a, b) = [2, 1] # SyntaxError 2 < 1 or (a, b = 2, 1) # Works 2 < 1 or (a, b = [2, 1]) # Works ``` Based on the precedence rules I've been able to find, all of these should work. Believe it or not, there are cases where using `and` or `or` in a stanza of lines is much more readable. Should the parser allow all of these? See attached driver script to reproduce this output. ---Files-------------------------------- driver.rb (1.17 KB) and-or-masgn-18242.diff (963 Bytes) driver.rb (2.1 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:ruby-core-request@ruby-lang.org?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>