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Backslash sequence inTcl Posted by skumar003 (skumar003), 6 February 2003 What is the use of backslash sequence in Tcl?Eg: set path [pwd] set tcc \\ set path &path$tcc where is my path finally set to? Is this for use in windows to fetch a file? Cheers, Posted by admin (Graham Ellis), 7 February 2003 The \ character in Tcl gives an alternative meaning to the next chartacter. If you write backslash followed by a special character, then the following character is not treated as special - you're telling Tcl that you REALLY want that second character as just a normal character, even if it would normally do something special. If you write a backslash followed by a letter or digit, then the following character has a special significance not normally associated with it. Examples \$ I want a $ character \\ I really want a \ character \n I want a newline character Your example code set path [pwd] set path to contain the result of running the pwd command set tcc \\ set tcc to contain a single \ character set path &path$tcc overwrite path with the string "&path" followed by the contents of the variable tcc, giving &path\ A further complication of \ ... It ALSO has special meanings in regular expressions, and if you need to have it in a regular expression you have to get it through the Tcl interpretter. Thus it's quite common to see a regular expression command than includes something like \\\* which means "I REALLY want to look for a *". The Tcl interpretter reduces the string above to \* which is the "I really want a *" to the regular expression handler. This page is a thread posted to the opentalk forum
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