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Correctly identify all known void value expressions
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Use the Parser library and bail on shitty regexes
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@JoshCheek
JoshCheek committed Jun 16, 2013
1 parent 1db75a6 commit 259a6f9
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2 changes: 2 additions & 0 deletions Readme.md
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Expand Up @@ -142,10 +142,12 @@ Known Issues

* `BEGIN/END` breaks things and I probably won't take the time to fix it, becuase it's nontrivial and its really meant for command-line scripts, but there is currently a cuke for it
* Heredocs aren't recorded. It might actually be possible if the ExpressionList were to get smarter
* Conflicts with libs that have `at_exit` blocks (e.g. minitest/autorun)

Todo
====

* Move as much of the SyntaxAnalyzer as possible over to Parser and ditch Ripper altogether
* Refactor ExpressionList/SeeingIsBelieving to store lines in an array instead of as a string, so everyone doesn't magically need to know when to chomp
* Make friends who actually know how to parse Ruby syntax (omg, teach me Ripper, pls, it will make this lib so much better, you have no idea O.o)

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25 changes: 16 additions & 9 deletions lib/seeing_is_believing/syntax_analyzer.rb
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@@ -1,4 +1,5 @@
require 'ripper'
require 'parser/current'

class SeeingIsBelieving
class SyntaxAnalyzer < Ripper::SexpBuilder
Expand Down Expand Up @@ -156,15 +157,21 @@ def on_comment(*)

# RETURNS

# this is conspicuosuly inferior, but I can't figure out how to actually parse it
# see: http://www.ruby-forum.com/topic/4409633
def self.void_value_expression?(code)
return true if /(^|\s)(?:return|next|redo|retry|break)([^\w\n]|\n?\z).*?\n?\z/ =~ code

lines = code.split("\n")
if /^if/ =~ lines[0].strip
return /return/ =~ lines[0] if lines.length == 1 # err on the side of conservativity
void_value_expression?(lines[-2])
def self.void_value_expression?(code_or_ast)
ast = code_or_ast
ast = Parser::CurrentRuby.parse(code_or_ast) if code_or_ast.kind_of? String

case ast && ast.type
when :begin, :resbody
void_value_expression?(ast.children[-1])
when :rescue, :ensure
ast.children.any? { |child| void_value_expression? child }
when :if
void_value_expression?(ast.children[1]) || void_value_expression?(ast.children[2])
when :return, :next, :redo, :retry, :break
true
else
false
end
end

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1 change: 1 addition & 0 deletions seeing_is_believing.gemspec
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Expand Up @@ -19,6 +19,7 @@ Gem::Specification.new do |s|
s.executables = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
s.require_paths = ["lib"]

s.add_dependency "parser", "~> 1.4"
s.add_development_dependency "rake", "~> 10.0.3"
s.add_development_dependency "rspec", "~> 2.12.0"
s.add_development_dependency "cucumber", "~> 1.2.1"
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181 changes: 154 additions & 27 deletions spec/syntax_analyzer_spec.rb
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Expand Up @@ -171,48 +171,175 @@
end
end

shared_examples_for 'single line void_value_expression?' do |keyword|
it "`#{keyword}` returns true when the expression ends in #{keyword}", t:true do
shared_examples_for 'single line void_value_expression?' do |keyword, options={}|
specify "`#{keyword}` returns true when the expression ends in #{keyword} without an argument" do
described_class.void_value_expression?("#{keyword}").should be_true
described_class.void_value_expression?("#{keyword}(1)").should be_true
described_class.void_value_expression?("#{keyword} 1").should be_true
described_class.void_value_expression?("#{keyword} 1\n").should be_true
described_class.void_value_expression?("#{keyword} 1 if true").should be_true
described_class.void_value_expression?("#{keyword} 1 if false").should be_true
described_class.void_value_expression?("#{keyword} if true").should be_true
described_class.void_value_expression?("o.#{keyword}").should be_false
described_class.void_value_expression?(":#{keyword}").should be_false
described_class.void_value_expression?(":'#{keyword}'").should be_false
described_class.void_value_expression?("'#{keyword}'").should be_false
described_class.void_value_expression?("def a\n#{keyword} 1\nend").should be_false
described_class.void_value_expression?("-> {\n#{keyword} 1\n}").should be_false
described_class.void_value_expression?("Proc.new {\n#{keyword} 1\n}").should be_false
described_class.void_value_expression?("#{keyword}_something").should be_false
described_class.void_value_expression?("def a\n#{keyword}\nend").should be_false
described_class.void_value_expression?("-> {\n#{keyword}\n}").should be_false
described_class.void_value_expression?("Proc.new {\n#{keyword}\n}").should be_false
described_class.void_value_expression?("#{keyword}_something").should be_false
described_class.void_value_expression?("'#{keyword}\n#{keyword}\n#{keyword}'").should be_false

unless options[:no_args]
described_class.void_value_expression?("#{keyword}(1)").should be_true
described_class.void_value_expression?("#{keyword} 1").should be_true
described_class.void_value_expression?("#{keyword} 1\n").should be_true
described_class.void_value_expression?("#{keyword} 1 if true").should be_true
described_class.void_value_expression?("#{keyword} 1 if false").should be_true
described_class.void_value_expression?("def a\n#{keyword} 1\nend").should be_false
described_class.void_value_expression?("-> {\n#{keyword} 1\n}").should be_false
described_class.void_value_expression?("Proc.new {\n#{keyword} 1\n}").should be_false
described_class.void_value_expression?("#{keyword} \\\n1").should be_true
end
end

it "knows when an if statement ends in `#{keyword}`" do
# if
described_class.void_value_expression?("if true\n#{keyword}\nend").should be_true
described_class.void_value_expression?("if true\n #{keyword}\nend").should be_true
described_class.void_value_expression?("if true\n 1+1\n #{keyword}\nend").should be_true
described_class.void_value_expression?("if true\n #{keyword}\n 1+1\n end").should be_false
described_class.void_value_expression?("123 && if true\n #{keyword}\nend").should be_false
described_class.void_value_expression?("def m\n if true\n #{keyword}\nend\n end").should be_false
described_class.void_value_expression?("if true; #{keyword}; end").should be_true
described_class.void_value_expression?("if true; 1; end").should be_false

# if .. elsif
described_class.void_value_expression?("if true\n #{keyword}\n elsif true\n 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n end").should be_true
described_class.void_value_expression?("if true\n #{keyword}\n 2\n elsif true\n 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n 2\n end").should be_false

# if .. else
described_class.void_value_expression?("if true\n #{keyword}\n else 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n else\n #{keyword}\n end").should be_true
described_class.void_value_expression?("if true\n #{keyword}\n 2\n else 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n else\n #{keyword}\n 2\n end").should be_false

# if .. elsif .. else .. end
described_class.void_value_expression?("if true\n #{keyword}\nelsif true\n 1 else 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n else\n 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n elsif true\n #{keyword}\n else\n 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n else\n #{keyword}\n end").should be_true
described_class.void_value_expression?("if true\n #{keyword}\n 2\nelsif true\n 1 else 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n 2\n else\n 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n elsif true\n #{keyword}\n 2\n else\n 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n else\n #{keyword}\n 2\n end").should be_false

unless options[:no_args]
# if
described_class.void_value_expression?("if true\n#{keyword} 1\nend").should be_true
described_class.void_value_expression?("if true\n #{keyword} 1\nend").should be_true
described_class.void_value_expression?("if true\n 1+1\n #{keyword} 1\nend").should be_true
described_class.void_value_expression?("if true\n #{keyword} 1\n 1+1\n end").should be_false
described_class.void_value_expression?("123 && if true\n #{keyword} 1\nend").should be_false
described_class.void_value_expression?("def m\n if true\n #{keyword} 1\nend\n end").should be_false
described_class.void_value_expression?("if true; #{keyword} 1; end").should be_true
described_class.void_value_expression?("if true; 1; end").should be_false

# if .. elsif
described_class.void_value_expression?("if true\n #{keyword} 1\n elsif true\n 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n end").should be_true
described_class.void_value_expression?("if true\n #{keyword} 1\n 2\n elsif true\n 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n 2\n end").should be_false

# if .. else
described_class.void_value_expression?("if true\n #{keyword} 1\n else 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n else\n #{keyword}\n end").should be_true
described_class.void_value_expression?("if true\n #{keyword} 1\n 2\n else 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n else\n #{keyword}\n 2\n end").should be_false

# if .. elsif .. else .. end
described_class.void_value_expression?("if true\n #{keyword} 1\nelsif true\n 1 else 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n else\n 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n elsif true\n #{keyword}\n else\n 1\n end").should be_true
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n else\n #{keyword}\n end").should be_true
described_class.void_value_expression?("if true\n #{keyword} 1\n 2\nelsif true\n 1 else 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n #{keyword}\n 2\n else\n 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n elsif true\n #{keyword}\n 2\n else\n 1\n end").should be_false
described_class.void_value_expression?("if true\n 1\n elsif true\n 1\n else\n #{keyword}\n 2\n end").should be_false
end
end

it "doesn't work because the return and next keyword evaluators are insufficient regexps" do
pending "doesn't pass yet (and prob never will >.<)" do
described_class.send(evalutor, "'#{keyword}\n#{keyword}\n#{keyword}'").should be_false
described_class.send(evalutor, "#{keyword} \\\n1").should be_true
it "knows when a begin statement ends in `#{keyword}`" do
described_class.void_value_expression?("begin\n #{keyword}\n end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword}\n end").should be_true
described_class.void_value_expression?("begin\n #{keyword}\n 1\n end").should be_false
described_class.void_value_expression?("begin\n 1\n #{keyword}\n 1\n end").should be_false

unless options[:no_args]
described_class.void_value_expression?("begin\n #{keyword} '123' \n end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword} 456\n end").should be_true
described_class.void_value_expression?("begin\n #{keyword} :'789'\n 1\n end").should be_false
described_class.void_value_expression?("begin\n 1\n #{keyword} /101112/\n 1\n end").should be_false
end

# I don't know that the rest of these hold across all versions of Ruby since they make no fucking sense
# so even though some of them can technically be non-vve,
# I'm still going to call any one of them a vve
#
# e.g. (tested on 2.0)
# this is allowed
# -> { a = begin; return
# rescue; return
# ensure; return
# end }
# this is not
# -> { a = begin; return
# end }

# with rescue...
described_class.void_value_expression?("begin\n #{keyword}\n rescue\n #{keyword} end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword}\n rescue RuntimeError => e\n end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword}\n rescue RuntimeError\n end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword}\n rescue\n end").should be_true
described_class.void_value_expression?("begin\n 1\n rescue\n end").should be_false
described_class.void_value_expression?("begin\n 1\n rescue\n #{keyword}\n end").should be_true
described_class.void_value_expression?("begin\n 1\n rescue\n #{keyword}\n 1\n end").should be_false

unless options[:no_args]
described_class.void_value_expression?("begin\n #{keyword}\n rescue\n #{keyword} 1 end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword} 1\n rescue RuntimeError => e\n end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword} 1\n rescue RuntimeError\n end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword} :abc\n rescue\n end").should be_true
described_class.void_value_expression?("begin\n 1\n rescue\n #{keyword} 'abc'\n end").should be_true
described_class.void_value_expression?("begin\n 1\n rescue\n #{keyword} :abc\n 1\n end").should be_false
end

# with ensure
described_class.void_value_expression?("begin\n #{keyword}\n ensure\n #{keyword} end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword}\n ensure\n end").should be_true
described_class.void_value_expression?("begin\n 1\n ensure\n end").should be_false
described_class.void_value_expression?("begin\n 1\n ensure\n #{keyword}\n end").should be_true
described_class.void_value_expression?("begin\n 1\n ensure\n #{keyword}\n 1\n end").should be_false

unless options[:no_args]
described_class.void_value_expression?("begin\n #{keyword}\n ensure\n #{keyword} 1 end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword} 1\n ensure\n end").should be_true
described_class.void_value_expression?("begin\n 1\n #{keyword} :abc\n ensure\n end").should be_true
described_class.void_value_expression?("begin\n 1\n ensure\n #{keyword} 'abc'\n end").should be_true
described_class.void_value_expression?("begin\n 1\n ensure\n #{keyword} :abc\n 1\n end").should be_false
end

# with ensure and rescue
described_class.void_value_expression?("begin\n 1\n rescue\n 2\n ensure\n 3\n end").should be_false
described_class.void_value_expression?("begin\n #{keyword}\n rescue\n 2\n ensure\n 3\n end").should be_true
described_class.void_value_expression?("begin\n 1\n rescue\n #{keyword}\n ensure\n 3\n end").should be_true
described_class.void_value_expression?("begin\n 1\n rescue\n 2\n ensure\n #{keyword}\n end").should be_true
end
end

it_should_behave_like 'single line void_value_expression?', 'return'
it_should_behave_like 'single line void_value_expression?', 'next'
it_should_behave_like 'single line void_value_expression?', 'redo'
it_should_behave_like 'single line void_value_expression?', 'retry'
it_should_behave_like 'single line void_value_expression?', 'break'

it 'knows when an if statement evaluates to a void value expression' do
described_class.void_value_expression?("if true\nreturn 1\nend").should be_true
described_class.void_value_expression?("if true\n return 1\nend").should be_true
described_class.void_value_expression?("if true\n 1+1\n return 1\nend").should be_true
described_class.void_value_expression?("if true\n return 1\n 1+1\n end").should be_false
described_class.void_value_expression?("123 && if true\n return 1\nend").should be_false
described_class.void_value_expression?("def m\n if true\n return 1\nend\n end").should be_false
described_class.void_value_expression?("if true; return 1; end").should be_true
described_class.void_value_expression?("if true; 1; end").should be_false
end
it_should_behave_like 'single line void_value_expression?', 'redo', no_args: true
it_should_behave_like 'single line void_value_expression?', 'retry', no_args: true

it 'knows when a line opens the data segment' do
described_class.begins_data_segment?('__END__').should be_true
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1 comment on commit 259a6f9

@JoshCheek
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Now that we're using Parser, we probably don't really need this many tests, we can just trust it to parse correctly.

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