passing through values with line number information that look and act like Ruby natives

This commit is contained in:
Jeremy Ashkenas
2009-12-17 09:37:42 -05:00
parent 146b5694c2
commit 1590713576
5 changed files with 70 additions and 34 deletions

View File

@@ -1,36 +1,3 @@
class Scope
attr_reader :parent, :temp_variable
def initialize(parent=nil)
@parent = parent
@variables = {}
@temp_variable = @parent ? @parent.temp_variable : 'a'
end
# Look up a variable in lexical scope, or declare it if not found.
def find(name, remote=false)
found = check(name, remote)
return found if found || remote
@variables[name] = true
found
end
# Just check for the pre-definition of a variable.
def check(name, remote=false)
return true if @variables[name]
@parent && @parent.find(name, true)
end
# Find an available, short variable name.
def free_variable
@temp_variable.succ! while check(@temp_variable)
@variables[@temp_variable] = true
@temp_variable.dup
end
end
class Node
# Tabs are two spaces for pretty-printing.
TAB = ' '