From: merch-redmine@... Date: 2019-04-11T21:42:13+00:00 Subject: [ruby-core:92250] [Ruby trunk Bug#15708] Implicit numbered argument decomposes an array Issue #15708 has been updated by jeremyevans0 (Jeremy Evans). File single-implicit-arg-no-destructure.diff added Attached is a patch that will turn off destructuring if the only implicit block variable is `@1`: ```ruby # equivalent to proc{|x| x} proc{@1}.call([1,2]) # => [1, 2] # equivalent to proc{|_,x| x} proc{@2}.call([1,2]) # => 2 # equivalent to proc{|x,y| y; x} proc{@2; @1}.call([1,2]) # => 1 ``` I think this results in semantics that most people would expect, even if they don't like the implicit block argument syntax. ---------------------------------------- Bug #15708: Implicit numbered argument decomposes an array https://bugs.ruby-lang.org/issues/15708#change-77584 * Author: sawa (Tsuyoshi Sawada) * Status: Open * Priority: Normal * Assignee: * Target version: * ruby -v: 2.7.0dev * Backport: 2.4: UNKNOWN, 2.5: UNKNOWN, 2.6: UNKNOWN ---------------------------------------- In the following, `@1` refers to the entire item iterated: ```ruby a = [1, 2, 3] a.map{|x| x} # => [1, 2, 3] a.map{@1} # => [1, 2, 3] ``` whereas in the following, `@1` refers to the first item achieved by decomposing the item iterated, behaving the same as `x` given by `|(x)|` rather than by `|x|`: ```ruby a = [[1], [2], [3]] a.map{|x| x} # => [[1], [2], [3]] a.map{|(x)| x} # => [1, 2, 3] a.map{@1} # => [1, 2, 3] ``` Is this intended? ---Files-------------------------------- single-implicit-arg-no-destructure.diff (471 Bytes) -- https://bugs.ruby-lang.org/ Unsubscribe: