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 Tcl: regexp ?switches? expression string ?matchvar submatchvar ...?

Regular expression matching procedure.

• expression is the regular expression to be searched for.
• string is the string to be searched.
• matchvar is an optional variable to receive the total part of string that matched expression.
• submatchvar are optional variables to receive parenthesized subexpressions in expression. If there are more submatchvar's than parenthesized subexpressions the extra submatchvar's will be set to an empty string. If a parenthesized subexpression doesn't match the string, the corresponding submatchvar will be set to an empty string. If either the above conditions are true and -indices is selected, The submatchvar is set to "-1 -1".

Tcl: Regular Expressions

Optional Switches:

• -about - returns a list of information about the expression for debugging purposes.
• -expanded - enables use of the expanded regular expression syntax where whitespace and comments are ignored. Same as including (?x) embedded option.
• -indices - causes submatchvars to receive lists containing the position of the first and last matching characters, instead of the matching characters themselves.
• -line - enables newline-sensitive matching. With this flag '[^' bracket expressions and '.' never match newlines, '^' matches an empty string after any newline in addition to its normal function, and `$' matches an empty string before any newline in addition to its normal function. This flag is equivalent to specifying both -linestop and -lineanchor, or the (?n) embedded option.
• -linestop - Changes the behavior of `[^' bracket expressions and `.' so that they stop at newlines. This is the same as specifying the (?p) embedded option.
• -lineanchor - Changes the behavior of `^' and `$' (the ``anchors) so they match the beginning and end of a line respectively. This is the same as specifying the (?w) embedded option.
• -nocase - Causes upper-case characters in string to be treated as lower case during the matching process.
• -all - Causes the regular expression to be matched as many times as possible in the string, returning the total number of matches found. If this is specified with match variables, they will contain information for the last match only.
• -inline - Causes the command to return, as a list, the data that would otherwise be placed in match variables. When using -inline, match variables may not be specified. If used with -all, the list will be concatenated at each iteration, such that a flat list is always returned. For each match iteration, the command will append the overall match data, plus one element for each subexpression in the regular expression. Examples are: regexp -inline -- {\w(\w)} " inlined "

       => {in n}
       regexp -all -inline -- {\w(\w)} " inlined "
       => {in n li i ne e}
  

• -- - marks the end of switches.

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Notebook exported on Monday, 7 July 2008, 18:56:06 PM Eastern Daylight Time