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Mini Shell
Mini Shell
#--
#
#
#
# Copyright (c) 1999-2006 Minero Aoki
#
# This program is free software.
# You can distribute/modify this program under the same terms of ruby.
# see the file "COPYING".
#
#++
require 'racc'
require 'racc/compat'
require 'racc/grammar'
require 'racc/parserfilegenerator'
require 'racc/sourcetext'
require 'stringio'
module Racc
grammar = Grammar.define {
g = self
g.class = seq(:CLASS, :cname, many(:param), :RULE, :rules, option(:END))
g.cname = seq(:rubyconst) {|name|
@result.params.classname = name
}\
| seq(:rubyconst, "<", :rubyconst) {|c, _, s|
@result.params.classname = c
@result.params.superclass = s
}
g.rubyconst = separated_by1(:colon2, :SYMBOL) {|syms|
syms.map {|s| s.to_s }.join('::')
}
g.colon2 = seq(':', ':')
g.param = seq(:CONV, many1(:convdef), :END) {|*|
#@grammar.end_convert_block # FIXME
}\
| seq(:PRECHIGH, many1(:precdef), :PRECLOW) {|*|
@grammar.end_precedence_declaration true
}\
| seq(:PRECLOW, many1(:precdef), :PRECHIGH) {|*|
@grammar.end_precedence_declaration false
}\
| seq(:START, :symbol) {|_, sym|
@grammar.start_symbol = sym
}\
| seq(:TOKEN, :symbols) {|_, syms|
syms.each do |s|
s.should_terminal
end
}\
| seq(:OPTION, :options) {|_, syms|
syms.each do |opt|
case opt
when 'result_var'
@result.params.result_var = true
when 'no_result_var'
@result.params.result_var = false
when 'omit_action_call'
@result.params.omit_action_call = true
when 'no_omit_action_call'
@result.params.omit_action_call = false
else
raise CompileError, "unknown option: #{opt}"
end
end
}\
| seq(:EXPECT, :DIGIT) {|_, num|
if @grammar.n_expected_srconflicts
raise CompileError, "`expect' seen twice"
end
@grammar.n_expected_srconflicts = num
}
g.convdef = seq(:symbol, :STRING) {|sym, code|
sym.serialized = code
}
g.precdef = seq(:LEFT, :symbols) {|_, syms|
@grammar.declare_precedence :Left, syms
}\
| seq(:RIGHT, :symbols) {|_, syms|
@grammar.declare_precedence :Right, syms
}\
| seq(:NONASSOC, :symbols) {|_, syms|
@grammar.declare_precedence :Nonassoc, syms
}
g.symbols = seq(:symbol) {|sym|
[sym]
}\
| seq(:symbols, :symbol) {|list, sym|
list.push sym
list
}\
| seq(:symbols, "|")
g.symbol = seq(:SYMBOL) {|sym| @grammar.intern(sym) }\
| seq(:STRING) {|str| @grammar.intern(str) }
g.options = many(:SYMBOL) {|syms| syms.map {|s| s.to_s } }
g.rules = option(:rules_core) {|list|
add_rule_block list unless list.empty?
nil
}
g.rules_core = seq(:symbol) {|sym|
[sym]
}\
| seq(:rules_core, :rule_item) {|list, i|
list.push i
list
}\
| seq(:rules_core, ';') {|list, *|
add_rule_block list unless list.empty?
list.clear
list
}\
| seq(:rules_core, ':') {|list, *|
next_target = list.pop
add_rule_block list unless list.empty?
[next_target]
}
g.rule_item = seq(:symbol)\
| seq("|") {|*|
OrMark.new(@scanner.lineno)
}\
| seq("=", :symbol) {|_, sym|
Prec.new(sym, @scanner.lineno)
}\
| seq(:ACTION) {|src|
UserAction.source_text(src)
}
}
GrammarFileParser = grammar.parser_class
if grammar.states.srconflict_exist?
raise 'Racc boot script fatal: S/R conflict in build'
end
if grammar.states.rrconflict_exist?
raise 'Racc boot script fatal: R/R conflict in build'
end
class GrammarFileParser # reopen
class Result
def initialize(grammar)
@grammar = grammar
@params = ParserFileGenerator::Params.new
end
attr_reader :grammar
attr_reader :params
end
def GrammarFileParser.parse_file(filename)
parse(File.read(filename), filename, 1)
end
def GrammarFileParser.parse(src, filename = '-', lineno = 1)
new().parse(src, filename, lineno)
end
def initialize(debug_flags = DebugFlags.new)
@yydebug = debug_flags.parse
end
def parse(src, filename = '-', lineno = 1)
@filename = filename
@lineno = lineno
@scanner = GrammarFileScanner.new(src, @filename)
@scanner.debug = @yydebug
@grammar = Grammar.new
@result = Result.new(@grammar)
@embedded_action_seq = 0
yyparse @scanner, :yylex
parse_user_code
@result.grammar.init
@result
end
private
def next_token
@scanner.scan
end
def on_error(tok, val, _values)
if val.respond_to?(:id2name)
v = val.id2name
elsif val.kind_of?(String)
v = val
else
v = val.inspect
end
raise CompileError, "#{location()}: unexpected token '#{v}'"
end
def location
"#{@filename}:#{@lineno - 1 + @scanner.lineno}"
end
def add_rule_block(list)
sprec = nil
target = list.shift
case target
when OrMark, UserAction, Prec
raise CompileError, "#{target.lineno}: unexpected symbol #{target.name}"
end
curr = []
list.each do |i|
case i
when OrMark
add_rule target, curr, sprec
curr = []
sprec = nil
when Prec
raise CompileError, "'=<prec>' used twice in one rule" if sprec
sprec = i.symbol
else
curr.push i
end
end
add_rule target, curr, sprec
end
def add_rule(target, list, sprec)
if list.last.kind_of?(UserAction)
act = list.pop
else
act = UserAction.empty
end
list.map! {|s| s.kind_of?(UserAction) ? embedded_action(s) : s }
rule = Rule.new(target, list, act)
rule.specified_prec = sprec
@grammar.add rule
end
def embedded_action(act)
sym = @grammar.intern("@#{@embedded_action_seq += 1}".intern, true)
@grammar.add Rule.new(sym, [], act)
sym
end
#
# User Code Block
#
def parse_user_code
line = @scanner.lineno
_, *blocks = *@scanner.epilogue.split(/^----/)
blocks.each do |block|
header, *body = block.lines.to_a
label0, paths = *header.sub(/\A-+/, '').split('=', 2)
label = canonical_label(label0)
(paths ? paths.strip.split(' ') : []).each do |path|
add_user_code label, SourceText.new(File.read(path), path, 1)
end
add_user_code label, SourceText.new(body.join(''), @filename, line + 1)
line += (1 + body.size)
end
end
USER_CODE_LABELS = {
'header' => :header,
'prepare' => :header, # obsolete
'inner' => :inner,
'footer' => :footer,
'driver' => :footer # obsolete
}
def canonical_label(src)
label = src.to_s.strip.downcase.slice(/\w+/)
unless USER_CODE_LABELS.key?(label)
raise CompileError, "unknown user code type: #{label.inspect}"
end
label
end
def add_user_code(label, src)
@result.params.public_send(USER_CODE_LABELS[label]).push src
end
end
class GrammarFileScanner
def initialize(str, filename = '-')
@lines = str.b.split(/\n|\r\n|\r/)
@filename = filename
@lineno = -1
@line_head = true
@in_rule_blk = false
@in_conv_blk = false
@in_block = nil
@epilogue = ''
@debug = false
next_line
end
attr_reader :epilogue
def lineno
@lineno + 1
end
attr_accessor :debug
def yylex(&block)
unless @debug
yylex0(&block)
else
yylex0 do |sym, tok|
$stderr.printf "%7d %-10s %s\n", lineno(), sym.inspect, tok.inspect
yield [sym, tok]
end
end
end
private
def yylex0
begin
until @line.empty?
@line.sub!(/\A\s+/, '')
if /\A\#/ =~ @line
break
elsif /\A\/\*/ =~ @line
skip_comment
elsif s = reads(/\A[a-zA-Z_]\w*/)
yield [atom_symbol(s), s.intern]
elsif s = reads(/\A\d+/)
yield [:DIGIT, s.to_i]
elsif ch = reads(/\A./)
case ch
when '"', "'"
yield [:STRING, eval(scan_quoted(ch))]
when '{'
lineno = lineno()
yield [:ACTION, SourceText.new(scan_action(), @filename, lineno)]
else
if ch == '|'
@line_head = false
end
yield [ch, ch]
end
else
end
end
end while next_line()
yield nil
end
def next_line
@lineno += 1
@line = @lines[@lineno]
if not @line or /\A----/ =~ @line
@epilogue = @lines.join("\n")
@lines.clear
@line = nil
if @in_block
@lineno -= 1
scan_error! sprintf('unterminated %s', @in_block)
end
false
else
@line.sub!(/(?:\n|\r\n|\r)\z/, '')
@line_head = true
true
end
end
ReservedWord = {
'right' => :RIGHT,
'left' => :LEFT,
'nonassoc' => :NONASSOC,
'preclow' => :PRECLOW,
'prechigh' => :PRECHIGH,
'token' => :TOKEN,
'convert' => :CONV,
'options' => :OPTION,
'start' => :START,
'expect' => :EXPECT,
'class' => :CLASS,
'rule' => :RULE,
'end' => :END
}
def atom_symbol(token)
if token == 'end'
symbol = :END
@in_conv_blk = false
@in_rule_blk = false
else
if @line_head and not @in_conv_blk and not @in_rule_blk
symbol = ReservedWord[token] || :SYMBOL
else
symbol = :SYMBOL
end
case symbol
when :RULE then @in_rule_blk = true
when :CONV then @in_conv_blk = true
end
end
@line_head = false
symbol
end
def skip_comment
@in_block = 'comment'
until m = /\*\//.match(@line)
next_line
end
@line = m.post_match
@in_block = nil
end
$raccs_print_type = false
def scan_action
buf = String.new
nest = 1
pre = nil
@in_block = 'action'
begin
pre = nil
if s = reads(/\A\s+/)
# does not set 'pre'
buf << s
end
until @line.empty?
if s = reads(/\A[^'"`{}%#\/\$]+/)
buf << (pre = s)
next
end
case ch = read(1)
when '{'
nest += 1
buf << (pre = ch)
when '}'
nest -= 1
if nest == 0
@in_block = nil
buf.sub!(/[ \t\f]+\z/, '')
return buf
end
buf << (pre = ch)
when '#' # comment
buf << ch << @line
break
when "'", '"', '`'
buf << (pre = scan_quoted(ch))
when '%'
if literal_head? pre, @line
# % string, regexp, array
buf << ch
case ch = read(1)
when /[qQx]/n
buf << ch << (pre = scan_quoted(read(1), '%string'))
when /wW/n
buf << ch << (pre = scan_quoted(read(1), '%array'))
when /s/n
buf << ch << (pre = scan_quoted(read(1), '%symbol'))
when /r/n
buf << ch << (pre = scan_quoted(read(1), '%regexp'))
when /[a-zA-Z0-9= ]/n # does not include "_"
scan_error! "unknown type of % literal '%#{ch}'"
else
buf << (pre = scan_quoted(ch, '%string'))
end
else
# operator
buf << '||op->' if $raccs_print_type
buf << (pre = ch)
end
when '/'
if literal_head? pre, @line
# regexp
buf << (pre = scan_quoted(ch, 'regexp'))
else
# operator
buf << '||op->' if $raccs_print_type
buf << (pre = ch)
end
when '$' # gvar
buf << ch << (pre = read(1))
else
raise 'racc: fatal: must not happen'
end
end
buf << "\n"
end while next_line()
raise 'racc: fatal: scan finished before parser finished'
end
def literal_head?(pre, post)
(!pre || /[a-zA-Z_0-9]/n !~ pre[-1,1]) &&
!post.empty? && /\A[\s\=]/n !~ post
end
def read(len)
s = @line[0, len]
@line = @line[len .. -1]
s
end
def reads(re)
m = re.match(@line) or return nil
@line = m.post_match
m[0]
end
def scan_quoted(left, tag = 'string')
buf = left.dup
buf = "||#{tag}->" + buf if $raccs_print_type
re = get_quoted_re(left)
sv, @in_block = @in_block, tag
begin
if s = reads(re)
buf << s
break
else
buf << @line
end
end while next_line()
@in_block = sv
buf << "<-#{tag}||" if $raccs_print_type
buf
end
LEFT_TO_RIGHT = {
'(' => ')',
'{' => '}',
'[' => ']',
'<' => '>'
}
CACHE = {}
def get_quoted_re(left)
term = Regexp.quote(LEFT_TO_RIGHT[left] || left)
CACHE[left] ||= /\A[^#{term}\\]*(?:\\.[^\\#{term}]*)*#{term}/
end
def scan_error!(msg)
raise CompileError, "#{lineno()}: #{msg}"
end
end
end # module Racc
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