From: jrafanie@... Date: 2015-12-23T20:24:43+00:00 Subject: [ruby-core:72459] [Ruby trunk - Feature #11868] Proposal for RubyVM::InstructionSequence.compile to return an object containing the syntax error information currently written to STDERR Issue #11868 has been updated by Joe Rafaniello. Note: I also tried ripper and all methods return nil for invalid syntax so RubyVM::InstructionSequence seemed like the easiest place to do this feature since it already has the information I need. ---------------------------------------- Feature #11868: Proposal for RubyVM::InstructionSequence.compile to return an object containing the syntax error information currently written to STDERR https://bugs.ruby-lang.org/issues/11868#change-55750 * Author: Joe Rafaniello * Status: Open * Priority: Normal * Assignee: ---------------------------------------- Currently, RubyVM::InstructionSequence.compile or RubyVM::InstructionSequence.new return a new InstructionSequence for valid ruby. For invalid syntax, a SyntaxError is raised with a message of 'compile error'. Meanwhile, the useful information, line number(s) and hint(s) to the invalid syntax location, is printed on standard error. I am proposing this information be returned as an object in the event of a SyntaxError. For example, here's good syntax: ~~~ RubyVM::InstructionSequence.new("x =1") # => @> ~~~ Here's bad syntax: ~~~ RubyVM::InstructionSequence.new("puts 'hi'\n puts 'hi2'\n\nthis.is -> not -> valid $ruby:syntax") # => SyntaxError: compile error # The useful hint and line number(s) are on standard error: :4: syntax error, unexpected keyword_not, expecting keyword_do_LAMBDA or tLAMBEG this.is -> not -> valid $ruby:syntax ^ :4: syntax error, unexpected tGVAR, expecting keyword_do_LAMBDA or tLAMBEG this.is -> not -> valid $ruby:syntax ^ ~~~ Some ideas: 1. Add methods to all SyntaxError exceptions to get all parse failures. For example: `syntax_error.parse_failures.each {|f| puts f.lineno; puts f.hint }`. In the above example, it failed on line 4 twice and we see two "hints." 2. Create a new method to RubyVM::InstructionSequence to check ruby syntax that would allow us to see if the syntax is valid and if not, the lineno and 'hint' for each parse failure. Use case: Rubocop[a] and other utilities[b] are really complicated and check for valid ruby syntax by creating a process to run ruby -wc with the script. [a] https://github.com/bbatsov/rubocop/blob/86e1acf67794bf6dd5d65812b91df475e44fa320/spec/support/mri_syntax_checker.rb#L51-L63 [b] https://github.com/ManageIQ/manageiq/blob/6725fe52222c07d576a18126d2ff825ddc6dffd0/gems/pending/util/miq-syntax-checker.rb#L8-L13 It would be nice to remove all of this complexity and use RubyVM::InstructionSequence, which already has the information we need but in a more user friendly format. Thanks! Joe Rafaniello -- https://bugs.ruby-lang.org/ Unsubscribe: