better compiler docs

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Torsten Ruger 2015-05-08 14:55:01 +03:00
parent 6f2affaf36
commit c700a3aabe

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@ -1,12 +1,29 @@
module Compiler
# Compiling is the conversion of the AST into 2 things:
# - code (ie sequences of Instructions inside Blocks) carried by CompiledMethods
# - an object graph containing all the Methods, their classes and Constants
#
# Some compile methods just add code, some may add structure (ie Blocks) while
# others instantiate Class and Method objects
#
# Everything in ruby is an expression, ie returns a value. So the effect of every compile
# is that a value is put into the ReturnSlot of the current Message.
# The compile method (so every compile method) returns the value that it deposits which
# may be unknown Mystery value.
#
# The Compiler.compile uses a visitor patter to dispatch according to the class name of
# the expression. So a NameExpression is delegated to compile_name etc.
# This makes the dispatch extensible, ie Expressions may be added by external code,
# as long as matching compile methods are supplied too.
#
def self.compile expression , method
exp_name = expression.class.name.split("::").last.sub("Expression","").downcase
#puts "Expression #{exp_name}"
begin
self.send "compile_#{exp_name}".to_sym , expression, method
rescue NoMethodError => e
puts "no compile method foudn for " + exp_name
puts "No compile method found for " + exp_name
raise e
end
end