Class: Lisp::Tokenizer
Instance Attribute Summary collapse
-
#line_number ⇒ Object
readonly
Returns the value of attribute line_number.
Class Method Summary collapse
Instance Method Summary collapse
- #advance ⇒ Object
- #almost_eof? ⇒ Boolean
- #consume_token ⇒ Object
- #digit?(ch) ⇒ Boolean
- #divider?(ch) ⇒ Boolean
- #eof? ⇒ Boolean
- #graph?(ch) ⇒ Boolean
- #hex?(ch) ⇒ Boolean
- #init ⇒ Object
-
#initialize(src, absorb_space = true) ⇒ Tokenizer
constructor
A new instance of Tokenizer.
- #letter?(ch) ⇒ Boolean
- #next_token ⇒ Object
- #number?(ch) ⇒ Boolean
- #process_escapes(str) ⇒ Object
- #read_character ⇒ Object
- #read_next_token ⇒ Object
- #read_number(hex) ⇒ Object
- #read_string ⇒ Object
- #read_symbol ⇒ Object
- #space?(ch) ⇒ Boolean
- #symbol_character?(ch) ⇒ Boolean
Constructor Details
#initialize(src, absorb_space = true) ⇒ Tokenizer
Returns a new instance of Tokenizer.
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# File 'lib/rubylisp/tokenizer.rb', line 15 def initialize(src, absorb_space=true) @absorb_whitespace = absorb_space @source = src @position = 0 @lookahead_token = nil @lookahead_literal = '' @eof = false @almost_eof = false @curent_ch = nil @next_ch = nil @next_next_ch = nil init end |
Instance Attribute Details
#line_number ⇒ Object (readonly)
Returns the value of attribute line_number.
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# File 'lib/rubylisp/tokenizer.rb', line 5 def line_number @line_number end |
Class Method Details
.from_file(f) ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 11 def self.from_file(f) self.new(f) end |
.from_string(str, absorb_space = true) ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 7 def self.from_string(str, absorb_space=true) self.new(StringIO.new(str, "r"), absorb_space) end |
Instance Method Details
#advance ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 30 def advance if @source.eof? @eof = true @almost_eof = true @current_ch = nil @next_ch = nil else @current_ch = @source.readchar if @source.eof? @almost_eof = true @next_ch = nil else @next_ch = @source.readchar if @source.eof? @next_next_ch = nil else @next_next_ch = @source.readchar @source.ungetc(@next_next_ch) end @source.ungetc(@next_ch) end end end |
#almost_eof? ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 62 def almost_eof? @almost_eof end |
#consume_token ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 313 def consume_token @position = @source.pos @lookahead_token, @lookahead_literal = self.read_next_token consume_token if @lookahead_token == :COMMENT end |
#digit?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 74 def digit?(ch) ch =~ /[[:digit:]]/ end |
#divider?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 193 def divider?(ch) ch =~ /[[[:space:]]\(\)\{\}<>\[\]]/ end |
#graph?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 88 def graph?(ch) ch =~ /[[:graph:]]/ end |
#hex?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 70 def hex?(ch) ch =~ /[abcdefABCDEF]/ end |
#init ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 319 def init @line_number = 0 advance consume_token end |
#letter?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 66 def letter?(ch) ch =~ /[[:alpha:]]/ end |
#next_token ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 54 def next_token return @position, @lookahead_token, @lookahead_literal end |
#number?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 78 def number?(ch) digit?(ch) || (ch == '-' && digit?(@next_ch)) end |
#process_escapes(str) ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 151 def process_escapes(str) i = 0 processed_str = "" while i < str.length if str[i] == '\\' processed_str << if i < (str.length - 1) i += 1 case (str[i]) when 'n' "\n" when 't' "\t" when '\\' "\\" else "\\#{str[i]}" end else "\\" end else processed_str << str[i] end i += 1 end processed_str end |
#read_character ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 198 def read_character lit = "" lit << @current_ch advance while !eof? && !divider?(@current_ch) lit << @current_ch advance end return :CHARACTER, lit end |
#read_next_token ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 211 def read_next_token return :EOF, '' if eof? if @absorb_whitespace while space?(@current_ch) @line_number += 1 if @current_ch == "\n" advance @position = @source.pos return :EOF, '' if eof? end end if !@absorb_whitespace && space?(@current_ch) @line_number += 1 if @current_ch == "\n" advance return :WHITESPACE, " " elsif number?(@current_ch) return read_number(false) elsif @current_ch == '-' && number?(@next_ch) return read_number(false) elsif @current_ch == '#' && @next_ch == 'x' advance advance return read_number(true) elsif @current_ch == '"' advance return read_string elsif @current_ch == '#' && @next_ch == '\\' advance advance return read_character elsif @current_ch == '\'' && @next_ch == '{' advance advance return :QUOTE_LBRACE, "'{" elsif @current_ch == '\'' && @next_ch == '#' && @next_next_ch == '(' advance advance advance return :QUOTE_HASH_LPAREN, "'#(" elsif @current_ch == '\'' advance return :QUOTE, "'" elsif @current_ch == '`' advance return :BACKQUOTE, "`" elsif @current_ch == ',' && @next_ch == '@' advance advance return :COMMAAT, ",@" elsif @current_ch == ',' advance return :COMMA, "," elsif @current_ch == '(' advance return :LPAREN, "(" elsif @current_ch == '#' && @next_ch == '(' advance advance return :HASH_LPAREN, "#(" elsif @current_ch == ')' advance return :RPAREN, ")" elsif @current_ch == '{' advance return :LBRACE, "{" elsif @current_ch == '}' advance return :RBRACE, "}" elsif @current_ch == '[' advance return :LBRACKET, "[" elsif @current_ch == ']' advance return :RBRACKET, "]" elsif @current_ch == '.' && space?(@next_ch) advance return :PERIOD, "." elsif @current_ch == '.' && symbol_character?(@next_ch) return read_symbol elsif symbol_character?(@current_ch) return read_symbol elsif @current_ch == '#' && @next_ch == 't' advance advance return :TRUE, "#t" elsif @current_ch == '#' && @next_ch == 'f' advance advance return :FALSE, "#f" elsif @current_ch == ';' lit = "" while true return :COMMENT, lit if eof? || @current_ch == "\n" lit << @current_ch advance end else return :ILLEGAL, @current_ch end end |
#read_number(hex) ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 126 def read_number(hex) lit = "" if @current_ch == '-' lit << @current_ch advance end is_float = false while !eof? && (digit?(@current_ch) || (hex && hex?(@current_ch)) || (!hex && !is_float && @current_ch == '.')) is_float ||= !hex && (@current_ch == '.') lit << @current_ch advance end tok = if hex :HEXNUMBER elsif is_float :FLOAT else :NUMBER end return tok, lit end |
#read_string ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 180 def read_string lit = "" while !eof? && @current_ch != '"' lit << @current_ch advance end return :EOF, '' if eof? advance return :STRING, process_escapes(lit) end |
#read_symbol ⇒ Object
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# File 'lib/rubylisp/tokenizer.rb', line 97 def read_symbol lit = "" tok = nil if @current_ch == '.' lit << @current_ch advance tok = :FFI_SEND_SYMBOL end while !eof? && ((@current_ch == '.' && !symbol_character?(@next_ch) && tok.nil?) || (@current_ch == '/' && symbol_character?(@next_ch)) || (symbol_character?(@current_ch))) tok ||= :FFI_NEW_SYMBOL if @current_ch == '.' && !lit.empty? tok = :FFI_STATIC_SYMBOL if @current_ch == '/' && !lit.empty? lit << @current_ch advance end tok ||= :SYMBOL return tok, case tok when :SYMBOL, :FFI_STATIC_SYMBOL lit when :FFI_SEND_SYMBOL lit[1..-1] when :FFI_NEW_SYMBOL lit[0..-2] end end |
#space?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 83 def space?(ch) ch =~ /[[:space:]]/ end |
#symbol_character?(ch) ⇒ Boolean
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# File 'lib/rubylisp/tokenizer.rb', line 93 def symbol_character?(ch) graph?(ch) && !("();\"'`|[]{}#,.".include?(ch)) end |