perl2js

#!/usr/bin/perl

## rules of thumb
# no regex should contain a .
# most should be non-greedy

undef $/;

$source = join ('', <>);


## swap over functions with params
$source =~ s/
	(sub\s+)          # 1 sub
	(\w+?)            # 2 function
	(\s*{\s*)         # 3 {
	(my\s*)           # 4 my
	(\()              # 5 (
	([\$\w\s\,]*?)    # 6 $args    Can be $ letters or ,
	(\))              # 7 )
	(\s*=\s*\@_;)     # 8 = @_; 
	/function $2($6)$3/gmsx;

## swap over functions with no params
$source =~ s/
	(sub\s)           # 1 sub
	(\w+?)            # 2 function
	(\s*{\s*)         # 3 {
	/function $2()$3/gmsx;


## swap my for var
$source =~ s/
	(my)              # 1 my
	(\s+?)            # 2 
	/var$2/gmsx;


## swap my for var
$source =~ s/
	(\n\s*)           # 1
	(print)           # 2 print
	(.+?)             # 3 something
	(;)               # 4;
	/$1document.write($3 )$4/gmsx;


# swap out some escaped chars with unicode equivalents to keep it safe and easy for the other regex's
$source =~ s/\\\"/\\u0022/gmsx;
$source =~ s/\\\$/\\u0024/gmsx;


## swap variables inside " strings

sub replace_vars {
	($in) = @_;
	$in =~ s/
		(\$)              # 1 $
		(\w+)             # 2 var
		(\W|$)            # 3 stuff or end of line
		/\"+$1$2+\"$3/gmsx;
	return "\"$in\"";
}

$source =~ s/
	(")               # 1 "
	([^"]*)           # 2 stuff that ain't a "
	(")               # 3 "
	/replace_vars($2)/egmsx;


## Get rid of empty string literals
$source =~ s/
	(\+)              # 1 +
	(")               # 2 "
	(")               # 3 "
	//egmsx;
$source =~ s/
	(")               # 1 "
	(")               # 2 "
	(\+)              # 3 +
	//egmsx;


## replace static join function with String join method


$source =~ s/
	(join)            # 1 join
	(\s+)             # 2  
	(                 # 3 the delimiter
		('[^']*') # 4 a ' string
		|         # or
		("[^"]*") # 5 a " string
		|         # or
		(\$\w+)   # 6 variable
	)
	(,)               # 7 ,
	(\s+)             # 8 whitespace 
	(                 # 9 an array expression
		(@\w+)       # an array variable
	)
#	(;)               # 10 ;,
	/$9.join($3)/gmsx;


## convert @array literals 
$source =~ s/
	(=)               # 1 =
	(\s*)             # 2
	(\()              # 3 (
	(.*?)             # 4 values
	(\))              # 5 )
	/$1$2\[$4\]/gmsx;


## convert foreach loop 
$source =~ s/
	(foreach)         # 1 foreach
	(\s+)             # 2 whitespace
	(var)             # 3 var 
	(\s+)             # 4 whitespace
	(\$\w+)           # 5 var
	(\s*)             # 6 whitespace
	(\()              # 7 (
	(.*?)             # 8 array expression
	(\)\s*\{)         # 9 ) {
	/for $7$3$4_$5 in $8$9var $5 = $8\[_$5\];/gmsx;


## Template regex
#$source =~ s/
#	/>>>>>>>>>>>>>>>> 1:$1 | 2:$2 | 3:$3 | 4:$4 | 5:$5 | 6:$6 <<<<</gmsx;


#print $source;
#exit;


## get rid of $ on the front of vars
$source =~ s/
	(\$)              # 1 $
	(\w+)             # 2 var
	(\W|$)            # 3 stuff or end of line
	/$2$3/gmsx;

## get rid of @ on the front of arrays
$source =~ s/
	(\@)              # 1 @
	(\w+)             # 2 var
	(\W|$)            # 3 stuff or end of line
	/$2$3/gmsx;


## replace comments
$source =~ s/
	(\n)               # 1 new line
	([^\n]*)           # 2 some optional code
	(\#)               # 3 #
	([^\n]*)           # 4 the comment
	(?!\n)             # 5 end of line or file (zero width assertion)
	/$1$2\/\/$4$5/gmsx;


# swap join

# swap substring

# swap regex?


# swap out some escaped chars with unicode equivalents to keep it safe and easy for the other regex's
$source =~ s/\\u0022/\\"/gmsx;
$source =~ s/\\u0024/\\\$/gmsx;


# remove trailing 1;
$source =~ s/1;$//g;


print $source;