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This page describes the Masks unit as per Lazarus version 2.3



The masks unit provides classes and functions for pattern matching using wildcards, sets/ranges and/or literal characters.

Controlling how the mask is interpreted


TMaskOpcodes is defined as set of TMaskOpcode.
The TMaskOpcode enumeration type consist of:

Name Interpretation
mocAnyChar Treat ? as a wildcard to match exactly one char
mocAnyCharOrNone Treat [?] to match any char or the absence of a char
mocAnyText Treat * as a wildcard to mach zero or any mumber of chars
mocRange treat [a-c] to match either 'a', 'b' or 'c'. '-' is treated as a range indicator.

To have a literal '-' in a range, it must be the first character in the range: [-a-c] matches '-', 'a', 'b', or 'c'.

mocSet Treat [a-c] to match either 'a', '-' or 'c'
mocNegateGroup Treat [!a-c] to not match 'a', 'b', or 'c', but match any other char. Requires mocRange and/or mocSet
mocEscapeChar Treat EscapeChar (defaults to '\') to take the next char as a literal, so '\*' is treated as a literal '*'.

Predefined MaskOpcodes

The masks unit has some predefined MaskOpcodes constants.

Name Interpretation
AllMaskOpCodes Self explanatory.
MaskOpCodesDisableRange Do not interpret [ as the start of a range or set.
MaskOpCodesNoEscape Interpret [?] as a set with a literal question mark instead of 0..1 chars wildcard. Disable escaping.
DefaultMaskOpCodes Equals to MaskOpCodesNoEscape.

If no TMaskOpcodes parameter is supplied to one of the Matches methods or functions, DefaultMaskOpCodes is assumed.

Specific Windows Quirks

Windows mask works in a different mode than regular masks, it has many quirks and corner cases inherited from CP/M, then adapted to DOS (8.3) file names and adapted again for long file names.

TWindowsQuirks is defined as set of TWindowsQuirks. The TWindowsQuirk enumeration type consists of:

Name Example mask Interpretation
wqAnyExtension Anything*.* The filename is not required to have an extension
wqFilenameEnd Anything??.abc The '?' matches 1 or 0 chars (except '.')
wqExtension3More Matches but also* (so '*.pas' also matches with 'file.pas.bak')
wqEmptyIsAny Empty string matches anything, so acts like '*'
wqAllByExtension .abc Is treated as *.abc
wqNoExtension Anything*. Matches Anything* without extension

TWindowsQuirks can only be used in the Windows specfic classses and functions. The default value for those matching methods is [wqAnyExtension,wqFilenameEnd,wqEmptyIsAny,wqNoExtension]

Predefined TWindowsQuirks

The masks unit has some predefined WindowsQuirks constants.

Name Interpretation
AllWindowsQuirks Self explanatory.
DefaultWindowsQuirks Do not support wqExtension3More and wqAllByExtension

If no TMaskOpcodes parameter is supplied to one of the Windows specific Matches methods or functions, DefaultWindowsQuirks is assumed.