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Modules: Synthesis

Constant Summary collapse

EOF =

jsmin.rb 2007-07-20 Author: Uladzislau Latynski This work is a translation from C to Ruby of jsmin.c published by Douglas Crockford. Permission is hereby granted to use the Ruby version under the same conditions as the jsmin.c on which it is based.

/* jsmin.c

2003-04-21

Copyright © 2002 Douglas Crockford (www.crockford.com)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

The Software shall be used for Good, not Evil.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

-1

Instance Method Summary collapse

Instance Method Details

#action(a) ⇒ Object

action – do something! What you do is determined by the argument: 1 Output A. Copy B to A. Get the next B. 2 Copy B to A. Get the next B. (Delete A). 3 Get the next B. (Delete B). action treats a string as a single character. Wow! action recognizes a regular expression if it is preceded by ( or , or =.



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# File 'lib/jsmin.rb', line 102

def action(a)
    if(a==1)
        $stdout.write $theA
    end
    if(a==1 || a==2)
        $theA = $theB
        if ($theA == "\'" || $theA == "\"")
            while (true)
                $stdout.write $theA
                $theA = get
                break if ($theA == $theB)
                raise "Unterminated string literal" if ($theA <= "\n")
                if ($theA == "\\")
                    $stdout.write $theA
                    $theA = get
                end
            end
        end
    end
    if(a==1 || a==2 || a==3)
        $theB = mynext
        if ($theB == "/" && ($theA == "(" || $theA == "," || $theA == "=" ||
                             $theA == ":" || $theA == "[" || $theA == "!" ||
                             $theA == "&" || $theA == "|" || $theA == "?" ||
                             $theA == "{" || $theA == "}" || $theA == ";" ||
                             $theA == "\n"))
            $stdout.write $theA
            $stdout.write $theB
            while (true)
                $theA = get
                if ($theA == "/")
                    break
                elsif ($theA == "\\")
                    $stdout.write $theA
                    $theA = get
                elsif ($theA <= "\n")
                    raise "Unterminated RegExp Literal"
                end
                $stdout.write $theA
            end
            $theB = mynext
        end
    end
end

#get ⇒ Object

get – return the next character from stdin. Watch out for lookahead. If the character is a control character, translate it to a space or linefeed.



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# File 'lib/jsmin.rb', line 49

def get()
  c = $stdin.getc
  return EOF if(!c)
  c = c.chr
  return c if (c >= " " || c == "\n" || c.unpack("c") == EOF)
  return "\n" if (c == "\r")
  return " "
end

#isAlphanum(c) ⇒ Object

isAlphanum – return true if the character is a letter, digit, underscore, dollar sign, or non-ASCII character



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# File 'lib/jsmin.rb', line 40

def isAlphanum(c)
   return false if !c || c == EOF
   return ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') ||
           (c >= 'A' && c <= 'Z') || c == '_' || c == '$' ||
           c == '\\' || c[0] > 126)
end

#jsmin ⇒ Object

jsmin – Copy the input to the output, deleting the characters which are insignificant to JavaScript. Comments will be removed. Tabs will be replaced with spaces. Carriage returns will be replaced with linefeeds. Most spaces and linefeeds will be removed.



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# File 'lib/jsmin.rb', line 151

def jsmin
    $theA = "\n"
    action(3)
    while ($theA != EOF)
        case $theA
        when " "
            if (isAlphanum($theB))
                action(1)
            else
                action(2)
            end
        when "\n"
            case ($theB)
            when "{","[","(","+","-"
                action(1)
            when " "
                action(3)
            else
                if (isAlphanum($theB))
                    action(1)
                else
                    action(2)
                end
            end
        else
            case ($theB)
            when " "
                if (isAlphanum($theA))
                    action(1)
                else
                    action(3)
                end
            when "\n"
                case ($theA)
                when "}","]",")","+","-","\"","\\", "'", '"'
                    action(1)
                else
                    if (isAlphanum($theA))
                        action(1)
                    else
                        action(3)
                    end
                end
            else
                action(1)
            end
        end
    end
end

#mynext ⇒ Object

mynext – get the next character, excluding comments. peek() is used to see if a ‘/’ is followed by a ‘/’ or ‘*’.



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# File 'lib/jsmin.rb', line 67

def mynext()
    c = get
    if (c == "/")
        if(peek == "/")
            while(true)
                c = get
                if (c <= "\n")
                return c
                end
            end
        end
        if(peek == "*")
            get
            while(true)
                case get
                when "*"
                   if (peek == "/")
                        get
                        return " "
                    end
                when EOF
                    raise "Unterminated comment"
                end
            end
        end
    end
    return c
end

#peek ⇒ Object

Get the next character without getting it.



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# File 'lib/jsmin.rb', line 59

def peek()
    lookaheadChar = $stdin.getc
    $stdin.ungetc(lookaheadChar)
    return lookaheadChar.chr
end