diff options
| -rw-r--r-- | txr.1 | 33 |
1 files changed, 20 insertions, 13 deletions
@@ -248,25 +248,32 @@ but has run out of files to process, the match fails. sends errors and verbose logs to the standard error device. The following paragraphs apply when .B TXR -is run without enabling verbose mode. If verbose mode is enabled, then -.B TXR -issues diagnostics on the standard error device even in situations which are -not erroneous. +is run without enabling verbose mode with -v, or the printing of variable +bindings with -B or -a. If the command line arguments are incorrect, or the query has a malformed -syntax, or fails to match, +syntax, .B TXR issues an error diagnostic and terminates with a failed status. +If the query fails due to a mismatch, +.B TXR +terminates with a failed status. No diagnostics are issued. + If the query is well-formed, and matches, then .B TXR -issues no diagnostics on standard error (except in the case of verbose -reporting enabled by -v). If no variables were bound in the query, then -nothing is printed on standard output. If the query has matched one or more -variables, then these variables are printed on standard output, in the form of -a shell script which, when evaluated, will cause shell variables to be -assigned. Printing of these variables is suppressed if the query executed one -or more @(output) directive directed to standard output. +issues no diagnostics, and terminates with a successful status. + +In verbose mode (-v), +.B TXR +issues diagnostics on the standard error device even in situations which are +not erroneous. + +In bindings-printing mode (-B or -a), +.B TXR +prints the word "false" if the query fails, and exits with a failed +termination status. If the query succeeds, the variable bindings, if any, +are output on standard output. .SH BASIC QUERY SYNTAX AND SEMANTICS @@ -15922,5 +15929,5 @@ does not contain a. The change in behavior of the % operator upon modifying the trailing context is not as intuitive as that of the * operator, because the trailing context is deeply involved in its logic. For single-character trailing contexts, it may be a good idea to use a complemented character class -instead. That is to say, rather than (.%a)bc, consider [^a]*bc. The set of +instead. That is to say, rather than (.%a)bc, consider [^a]*abc. The set of strings which don't contain the character a is adequately expressed by [^a]*. |