lib/cog/dsl/language_dsl.rb
module Cog
module DSL
# DSL for defining a language
class LanguageDSL
# @api developer
# @param key [String] unique case-insensitive identifier
def initialize(key)
@lang = Cog::Language.new key
end
# Define a readable name for the language
# @param value [String] readable name of the language
# @return [nil]
def name(value)
lang_eval { @name = value }
nil
end
# Define single line comment notation
# @param prefix [String] starts a single line comment in the language
# @return [nil]
def comment(prefix)
lang_eval { @comment_prefix = prefix }
nil
end
# Define multi-line comment notation
# @param prefix [String] starts a multi-line comment in the language
# @param postfix [String] ends a multi-line comment in the language
# @return [nil]
def multiline_comment(prefix, postfix)
lang_eval do
@multiline_comment_prefix = prefix
@multiline_comment_postfix = postfix
end
nil
end
# Borrow comment notation from another language
# @param lang_key [String] use comment notation from the language with the given key
# @return [nil]
def comment_style(lang_key)
lang_eval { @comment_style = lang_key.to_s.downcase }
nil
end
# Define file extensions
# @param values [Array<String>] list of file extensions for this language
# @return [nil]
def extension(*values)
lang_eval do
@extensions = values.collect {|key| key.to_s.downcase}
end
end
def seed_extension(ext, opt={})
lang_eval do
@seed_extension = ext.to_s.downcase
@seed_header = opt[:header].to_s.downcase if opt[:header]
end
end
# Define a block to call when using a named scopes in this language
# @yieldparam name [String] name of the scope to use
# @yieldreturn [String] a using named scope statement in this language
# @return [nil]
def use_named_scope(&block)
lang_eval { @use_named_scope_block = block }
nil
end
# Define a block to call when beginning a named scope in this language
# @yieldparam name [String] name of the scope to begin
# @yieldreturn [String] a begin named scope statement in this language
# @return [nil]
def named_scope_begin(&block)
lang_eval { @named_scope_begin_block = block }
nil
end
# Define a block to call when ending a named scope in this language
# @yieldparam name [String] name of the scope to end
# @yieldreturn [String] an end named scope statement in this language
# @return [nil]
def named_scope_end(&block)
lang_eval { @named_scope_end_block = block }
nil
end
# Define a block to call when beginning an include guard in this language
# @yieldparam name [String] name of the guard
# @yieldreturn [String] a begin guard in this language
# @return [nil]
def include_guard_begin(&block)
lang_eval { @include_guard_begin_block = block }
nil
end
# Define a block to call when ending an include guard in this language
# @yieldparam name [String] name of the guard
# @yieldreturn [String] an end guard in this language
# @return [nil]
def include_guard_end(&block)
lang_eval { @include_guard_end_block = block }
nil
end
# Borrow include guard notation from another language
# @param lang_key [String] use include guard notation from the language with the given key
# @return [nil]
def include_guard_style(lang_key)
lang_eval { @include_guard_style = lang_key.to_s.downcase }
nil
end
# Enumerate reserved identifiers in the language
# @param words [Array<String>] a list of words which must not be used as identifiers in the language
# @return [nil]
def reserved(words)
lang_eval { @reserved = words }
nil
end
# Map a cog primitive type to a native type in this language
# @param name [Symbol] name of the cog primitive type
# @param ident [String] identifier of the mapped type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_primitive(name, ident, &block)
lang_eval do
@prim_ident[name.to_sym] = ident.to_s
@prim_to_lit[name.to_sym] = block
end
nil
end
# Map the cog boolean type to a native type in this language
# @param ident [String] identifier of the boolean type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the boolean literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_boolean(ident, &block) ; map_primitive(:boolean, ident, &block) ; end
# Map the cog integer type to a native type in this language
# @param ident [String] identifier of the integer type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the integer literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_integer(ident, &block) ; map_primitive(:integer, ident, &block) ; end
# Map the cog long type to a native type in this language
# @param ident [String] identifier of the long type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the long literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_long(ident, &block) ; map_primitive(:long, ident, &block) ; end
# Map the cog float type to a native type in this language
# @param ident [String] identifier of the float type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the float literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_float(ident, &block) ; map_primitive(:float, ident, &block) ; end
# Map the cog double type to a native type in this language
# @param ident [String] identifier of the double type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the double literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_double(ident, &block) ; map_primitive(:double, ident, &block) ; end
# Map the cog char type to a native type in this language
# @param ident [String] identifier of the char type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the char literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_char(ident, &block) ; map_primitive(:char, ident, &block) ; end
# Map the cog string type to a native type in this language
# @param ident [String] identifier of the string type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the string literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_string(ident, &block) ; map_primitive(:string, ident, &block) ; end
# Map the cog null type to a native type in this language
# @param ident [String] identifier of the null type in this language
# @yieldparam obj [Object] a ruby object
# @yieldreturn [String,nil] the null literal representation of the given obj in this language, or +nil+ if the object can not be mapped
# @return [nil]
def map_null(ident, &block) ; map_primitive(:null, ident, &block) ; end
def map_void(ident) ; map_primitive(:void, ident) ; end
# @api developer
# Compute the comment pattern
# @return [Cog::Language] the defined language
def finalize
pattern = /[*]/
esc = lambda do |x|
x.gsub(pattern) {|match| "\\#{match}"}
end
lang_eval do
@include_guard_style ||= key
@comment_style ||= key
@comment_pattern = if @comment_prefix && @multiline_comment_prefix
'^\s*(?:%s|%s)\s*%%s\s*(?:%s)?\s*$' % [@comment_prefix, @multiline_comment_prefix, @multiline_comment_postfix].collect(&esc)
elsif @comment_prefix
'^\s*%s\s*%%s\s*$' % esc.call(@comment_prefix)
elsif @multiline_comment_prefix
'^\s*%s\s*%%s\s*%s\s*$' % [@multiline_comment_prefix, @multiline_comment_postfix].collect(&esc)
else
'^\s*%s\s*$'
end
end
@lang
end
private
def lang_eval(&block)
@lang.instance_eval &block
end
end
end
end