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Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 37 |
1 files changed, 27 insertions, 10 deletions
@@ -39934,7 +39934,7 @@ as its value. .coNP Pattern operator @ require .synb -.mets @(require < pattern << expression *) +.mets @(require < pattern << condition *) .syne .desc The pattern operator @@ -39944,19 +39944,36 @@ applies the specified to the corresponding object. If the .meta pattern -matches, the operator then imposes the additional conditions specified by -the extra -.metn expression . -The -.meta expression +matches, the operator then imposes the additional constraints +specified by zero or more +.meta condition +forms. +Each +.meta condition is evaluated in a scope in which the variables from .meta pattern have already been established. -However, the mach is considered to have succeeded only if -.meta expression -yields true. If it yields + +For the +.code require +operator to be a successful match, every +.meta condition +must evaluate true, otherwise the match fails. + +The +.meta condition +forms behave as if they were the arguments of an implicit +.code and +operator, which implies left-to-right evaluation behavior, stopping +evaluation on the first +.meta condition +which produces .codn nil , -then the match is deemed to have failed. +and defaulting to a result of +.code t +when no +.meta condition +forms are specified. .TP* Examples: |