Class: KPeg::CompiledParser
- Inherits:
-
Object
- Object
- KPeg::CompiledParser
show all
- Includes:
- Position
- Defined in:
- lib/kpeg/compiled_parser.rb
Defined Under Namespace
Classes: MemoEntry, ParseError, RuleInfo
Instance Attribute Summary collapse
Class Method Summary
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Instance Method Summary
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Methods included from Position
#current_column, #current_line, #lines
Constructor Details
#initialize(str, debug = false) ⇒ CompiledParser
This is distinct from setup_parser so that a standalone parser can redefine #initialize and still have access to the proper parser setup code.
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# File 'lib/kpeg/compiled_parser.rb', line 19
def initialize(str, debug=false)
setup_parser(str, debug)
end
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Instance Attribute Details
#failed_rule ⇒ Object
Returns the value of attribute failed_rule.
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# File 'lib/kpeg/compiled_parser.rb', line 134
def failed_rule
@failed_rule
end
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#failing_rule_offset ⇒ Object
Returns the value of attribute failing_rule_offset.
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# File 'lib/kpeg/compiled_parser.rb', line 41
def failing_rule_offset
@failing_rule_offset
end
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#pos ⇒ Object
Returns the value of attribute pos.
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# File 'lib/kpeg/compiled_parser.rb', line 42
def pos
@pos
end
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#result ⇒ Object
Returns the value of attribute result.
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# File 'lib/kpeg/compiled_parser.rb', line 42
def result
@result
end
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#string ⇒ Object
Returns the value of attribute string.
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# File 'lib/kpeg/compiled_parser.rb', line 40
def string
@string
end
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Class Method Details
.rule_info(name, rendered) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 334
def self.rule_info(name, rendered)
RuleInfo.new(name, rendered)
end
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Instance Method Details
#apply(rule) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 269
def apply(rule)
if m = @memoizations[rule][@pos]
@pos = m.pos
if !m.set
m.left_rec = true
return nil
end
@result = m.result
return m.ans
else
m = MemoEntry.new(nil, @pos)
@memoizations[rule][@pos] = m
start_pos = @pos
ans = __send__ rule
lr = m.left_rec
m.move! ans, @pos, @result
if ans and lr
return grow_lr(rule, nil, start_pos, m)
else
return ans
end
return ans
end
end
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#apply_with_args(rule, *args) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 234
def apply_with_args(rule, *args)
memo_key = [rule, args]
if m = @memoizations[memo_key][@pos]
@pos = m.pos
if !m.set
m.left_rec = true
return nil
end
@result = m.result
return m.ans
else
m = MemoEntry.new(nil, @pos)
@memoizations[memo_key][@pos] = m
start_pos = @pos
ans = __send__ rule, *args
lr = m.left_rec
m.move! ans, @pos, @result
if ans and lr
return grow_lr(rule, args, start_pos, m)
else
return ans
end
return ans
end
end
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#external_invoke(other, rule, *args) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 213
def external_invoke(other, rule, *args)
old_pos = @pos
old_string = @string
@pos = other.pos
@string = other.string
begin
if val = __send__(rule, *args)
other.pos = @pos
other.result = @result
else
other.set_failed_rule "#{self.class}##{rule}"
end
val
ensure
@pos = old_pos
@string = old_string
end
end
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#failure_caret ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 71
def failure_caret
l = current_line @failing_rule_offset
c = current_column @failing_rule_offset
line = lines[l-1]
"#{line}\n#{' ' * (c - 1)}^"
end
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#failure_character ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 79
def failure_character
l = current_line @failing_rule_offset
c = current_column @failing_rule_offset
lines[l-1][c-1, 1]
end
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#failure_info ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 59
def failure_info
l = current_line @failing_rule_offset
c = current_column @failing_rule_offset
if @failed_rule.kind_of? Symbol
info = self.class::Rules[@failed_rule]
"line #{l}, column #{c}: failed rule '#{info.name}' = '#{info.rendered}'"
else
"line #{l}, column #{c}: failed rule '#{@failed_rule}'"
end
end
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#failure_oneline ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 85
def failure_oneline
l = current_line @failing_rule_offset
c = current_column @failing_rule_offset
char = lines[l-1][c-1, 1]
if @failed_rule.kind_of? Symbol
info = self.class::Rules[@failed_rule]
"@#{l}:#{c} failed rule '#{info.name}', got '#{char}'"
else
"@#{l}:#{c} failed rule '#{@failed_rule}', got '#{char}'"
end
end
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#get_byte ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 157
def get_byte
if @pos >= @string.size
return nil
end
s = @string.getbyte @pos
@pos += 1
s
end
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#get_text(start) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 46
def get_text(start)
@string[start..@pos-1]
end
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#grow_lr(rule, args, start_pos, m) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 303
def grow_lr(rule, args, start_pos, m)
while true
@pos = start_pos
@result = m.result
if args
ans = __send__ rule, *args
else
ans = __send__ rule
end
return nil unless ans
break if @pos <= m.pos
m.move! ans, @pos, @result
end
@result = m.result
@pos = m.pos
return m.ans
end
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#match_string(str) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 136
def match_string(str)
len = str.size
if @string[pos,len] == str
@pos += len
return str
end
return nil
end
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#parse(rule = nil) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 178
def parse(rule=nil)
if !rule
apply(:_root)
else
method = rule.gsub("-","_hyphen_")
apply :"_#{method}"
end
end
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#raise_error ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 102
def raise_error
raise ParseError, failure_oneline
end
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#scan(reg) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 146
def scan(reg)
if m = reg.match(@string[@pos..-1])
width = m.end(0)
@pos += width
return true
end
return nil
end
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#set_failed_rule(name) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 127
def set_failed_rule(name)
if @pos > @failing_rule_offset
@failed_rule = name
@failing_rule_offset = @pos
end
end
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#setup_foreign_grammar ⇒ Object
Must be outside the STANDALONE block because a standalone parser always injects it’s own version of this method.
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# File 'lib/kpeg/compiled_parser.rb', line 8
def setup_foreign_grammar
end
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#setup_parser(str, debug = false) ⇒ Object
Prepares for parsing str
. If you define a custom initialize you must call this method before #parse
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# File 'lib/kpeg/compiled_parser.rb', line 29
def setup_parser(str, debug=false)
@string = str
@pos = 0
@memoizations = Hash.new { |h,k| h[k] = {} }
@result = nil
@failed_rule = nil
@failing_rule_offset = -1
setup_foreign_grammar
end
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#show_error(io = STDOUT) ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 106
def show_error(io=STDOUT)
error_pos = @failing_rule_offset
line_no = current_line(error_pos)
col_no = current_column(error_pos)
io.puts "On line #{line_no}, column #{col_no}:"
if @failed_rule.kind_of? Symbol
info = self.class::Rules[@failed_rule]
io.puts "Failed to match '#{info.rendered}' (rule '#{info.name}')"
else
io.puts "Failed to match rule '#{@failed_rule}'"
end
io.puts "Got: #{string[error_pos,1].inspect}"
line = lines[line_no-1]
io.puts "=> #{line}"
io.print(" " * (col_no + 3))
io.puts "^"
end
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#show_pos ⇒ Object
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# File 'lib/kpeg/compiled_parser.rb', line 50
def show_pos
width = 10
if @pos < width
"#{@pos} (\"#{@string[0,@pos]}\" @ \"#{@string[@pos,width]}\")"
else
"#{@pos} (\"... #{@string[@pos - width, width]}\" @ \"#{@string[@pos,width]}\")"
end
end
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