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Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 12 |
1 files changed, 12 insertions, 0 deletions
@@ -572,6 +572,11 @@ The forms with an * indicate a long match, see Longest Match below. The last two forms with the embedded regexp /RE/ or number have special semantics, see Positive Match below. +The identifier t cannot be used as a name; it is a reserved symbol which +denotes the value true. An attempt to use the variable @t will result +in an exception. The symbol nil can be used as a variable name, +but it has special semantics, described in a section below. + When the @NAME form is used, the name itself may consist of any combination of one or more letters, numbers, and underscores. It may not look like a number, so that for instance 123 is not a valid name, but 12A is valid. Case is @@ -820,6 +825,13 @@ This syntax is processed without consideration of what other syntax follows. A positive match may be directly followed by an unbound variable. +.SS Symbol nil as a Variable + +If the symbol nil is used as a variable, it behaves like a variable which +has no binding. Furthermore, no binding is created. @nil allows the +variable matching syntax to be used to skip material, in ways different +from and complementary to @(skip). + .SS Regular Expressions Regular expressions are a language for specifying sets of character strings. |