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ANSI Common Lisp  23 Reader 23.2 Dictionary of Reader
| 23.2.11 set-syntax-from-char |
Function |
- Syntax:
-
set-syntax-from-char
to-char from-char &optional to-readtable from-readtable
 t
- Arguments and Values:
-
to-char - a character.
from-char - a character.
to-readtable - a readtable.
The default is the current readtable.
from-readtable - a readtable designator.
The default is the standard readtable.
- Description:
-
set-syntax-from-char makes
the syntax of to-char in to-readtable be the same as
the syntax of from-char in from-readtable.
set-syntax-from-char copies the syntax types of from-char.
If from-char is a macro character,
its reader macro function is copied also.
If the character is a dispatching macro character,
its entire dispatch table of reader macro functions is copied.
The constituent traits of from-char are not copied.
A macro definition from a character such as
" can be copied to another character; the standard definition for "
looks for another character that is the same as the character that
invoked it. The definition of ( can not be meaningfully copied
to {, on the other hand.
The result is that lists are of the form
{a b c), not {a b c},
because the definition
always looks for a closing parenthesis, not a closing brace.
- Examples:
-
(set-syntax-from-char #\7 #\;) T
123579 1235
- Side Effects:
-
The to-readtable is modified.
- Affected By:
-
The existing values in the from-readtable.
- See Also:
-
set-macro-character,
make-dispatch-macro-character,
Section 2.1.4 Character Syntax Types
- Notes:
-
The constituent traits of a character are "hard wired"
into the parser for extended tokens. For example, if the definition
of S is copied to *, then * will become a constituent
that is alphabetic2 but that cannot be used as a
short float exponent marker.
For further information, see Section 2.1.4.2 Constituent Traits.
- Allegro CL Implementation Details:
-
None.
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