diff options
| -rw-r--r-- | txr.1 | 27 |
1 files changed, 11 insertions, 16 deletions
@@ -14481,11 +14481,6 @@ foo; it is local inside it. .SH QUOTE/QUASIQUOTE OPERATOR SYNTAX -The quasiquote read syntax has a target language made up of operators. The TXR -parser rewrites the syntax into the appropriate combination of these operators, -and automatically selects whether a form is based on the quote operator or the -qquote operator. The operators are described below. - .SS Operator quote .TP @@ -14501,8 +14496,7 @@ and instead returns <form> itself as an object. For example, if <form> is a symbol, then <form> is not evaluated to the symbol's value; rather the symbol itself is returned. -Note: when the quote syntax '<form> is used, then if <form> is not a list -structure which contains unquotes or splices, it is translated to +Note: when the quote syntax '<form> is used it is translated to (quote <form>). .TP @@ -14578,9 +14572,10 @@ compilation and processes its interior. .TP Dialect note: -In Lisp dialects which have a published syntax, there is the expectation -that the quasiquote read syntax corresponds to it. That is to say, that -for instance ^(a b ,c) is translated to (qquote b (unquote c)). +In Lisp dialects which have a published quasiquoting operator syntax, there is +the expectation that the quasiquote read syntax corresponds to it. That is to +say, that for instance the read syntax ^(a b ,c) is translated to +(qquote b (unquote c)). In TXR Lisp, this is not true! Although ^(b b ,c) is translated to a quasiquoting macro, it is an internal one, not based on the public qquote, @@ -14593,17 +14588,17 @@ since it doesn't treat them specially. This also allows programmers to use the quasiquote read syntax to construct quasiquote macros. For instance - ^(qquote (unquote ,x)) + ^(qquote (unquote ,x)) ;; does not mean ^^,x -does not mean ^^,x. To the quasiquote reader, the qquote and unquote symbols -mean nothing special, and so this syntax simply means that if the value of x is -foo, the result will be (qquote (unquote foo)). +To the quasiquote reader, the qquote and unquote symbols mean nothing special, +and so this syntax simply means that if the value of x is foo, the result will +be (qquote (unquote foo)). The form's expansion is actually this: (sys:qquote (qquote (unquote (sys:unquote x)))) -the sys:qquote macro recognizes sys:unquote embedded in the form, and +the sys:qquote macro recognizes sys:unquote embedded in the form, and the other symbols not in the sys: package are just static template material. .SS Operator unquote @@ -14621,7 +14616,7 @@ Description: The unquote operator is not an operator per se. The unquote symbol has no binding in the global environment. It is a special syntax that is recognized within a qquote form, to indicate forms within the quasiquote which are to be -evaluated and insertd into the resulting structure. +evaluated and inserted into the resulting structure. The variant (qquote (unquote <form>)) is equivalent to <form>: the qquote and unquote "cancel out". |