Replacing Text

The Replace family of functions is used to scan text (strings) (especially the contents of .html files) and replace certain non-terminal symbols with new values.

A non-terminal symbol is a sequence of characters representing a CW expression surrounded by begin- and end- delimiters.  The begin-delimiter and end-delimiter default to <? and ?>.  In an .html file these are coded as &lt;? and ?&gt;.  For more information on how Web browsers (and HTML editors) treat special characters, see Character Entities.

If you desire to use alternate begin- and end-delimiters, set the values of SpecialVariables["BeginExpression"] and SpecialVariables["EndExpression"]

The Replace functions are:

string Replace(string input, args ...) // replace using SpecialVariables delimiters

string Replace1(string input, args ...) // replace with (Non-encoded) <? and ?>

string Replace2(string input, string bs, string es, args ...) // specify delimiters explicitly

The arguments beginning at args are optional arguments.  If they are specified, they may be referenced using the expressions arg[0], arg[1], arg[2], etc.
a = '456';
b = '123<?a?>789';
c = Replace1(b);
Client << c;  // browser shows "123456789"

The expression within the delimiters may be any CW expression including function calls and local and global variables.

a1 = 450;
a2 = 6;
b = '123<?a1 + a2?>789';
c = Replace1(b);
Client << c;  // browser shows "123456789"

You may supply optional arguments:

b = '<?arg[0]?, arg[1]?, arg[2]?>';
c = Replace1(b, 'abc', 'def', 'ghi');
Client << c;  // browser shows "abc, def, ghi"

If you are reading a file created by an HTML editor, you probably want to use the standard (&lt;?, ?&gt;) delimiters.  Use the Replace function.

b =GetFile("x.html");
c = Replace1(b, 'abc', 'def', 'ghi');
Client << c;  // browser shows "abc, def, ghi"

You may replace the begin and end delimiters depending on your requirements.

SpecialVariables["BeginExpression"] = "aaa";
SpecialVariables["EndExpression"] = "bbb";
a = "Hello, world."
b = 'aaaabbb';
c = Replace(b);
Client << c;  // browser shows "Hello, world."