7.7
9 Generating identifiers
| (define-temp-ids maybe-concise simple-format base+ellipses | | maybe-first-base maybe-prefix) |
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| base+ellipses | | = | | base | | | | | | | (base+ellipses ooo) | | | | | | | | maybe-concise | | = | | | | | | | | | #:concise | | | | | | | | maybe-first-base | | = | | | | | | | | | #:first-base first-base | | | | | | | | maybe-prefix | | = | | | | | | | | | #:prefix prefix |
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Defines
new-name as a syntax attribute, with the same nested
structure as
base. The
new-name is obtained by applying the
base to the given
simple-format string. The generated syntax
contains identifiers derived using the
base and
simple-format in the same way. Each of the generated identifiers is
unique, in the sense that there are not two generated identifiers which are
free-identifier=? to each other.
If the #:first-base option is specified, then new-first is
also defined to be the first generated identifier in the whole tree. In other
words, new-first will be bound to the same identifier as
new-name if there are no ellipses, to the value of
(stx-car new-name) if there is one level of ellipses, to the value
of (stx-car (stx-car new-name)) if there are two levels, and so on.
The identifier new-first is generated by applying
first-base to the simple-format.
If the #:prefix option is specified, then the generated identifiers
are prefixed with prefix, followed by a colon ":". This does
not impact the new-name and new-first identifiers, so it
can be useful when succinct identifiers are desired for the syntax attributes
within the macro which uses define-temp-ids, but the generated
identifiers should contain more context, to improve the readability of error
messages which involve the generated temporary identifiers.
If the #:concise option is specified, then the generated identifiers
are more concise, which makes them easier to read when debugging macros, but
also means that two distinct identifiers can look the same (but have distinct
scopes). If the #:concise option is omitted, the generated identifiers
may contain extra characters do help visually disambiguate similar identifiers
(those extra characters are obtained using generate-temporary).
Changed in version 1.1 of package phc-toolkit: The lexical context for the defined identifier
new-name is now taken from the format, instead of being
taken from the base name. Previously, the lexical context
was taken from the base name, except when the simple format
did not contain any "~a", in which case it was taken from
the whole base+ellipses (this was a bug, which is fixed now
that both cases use the lexical context of format). The
same applies to the lexical context for new-first
9.1 Untyped versions of ids