4 ms·
The syntax is the same. Both are s-expressions. The difference is how a particular implementation interprets them. In this example, it would depend on the sem
by greydius 11y ago
The syntax is the same. Both are s-expressions. The difference is how a particular implementation interprets them. In this example, it would depend on the semantics of def.
- lispm 11y agoThat's only the syntax of s-expressions - a data format. The Lisp syntax is defined on top of s-expressions. For example Common Lisp has a CASE operator. That's the EBNF syntax: case keyform {normal-clause}* [otherwise-clause] => result* normal-clause::= (keys form*) otherwise-clause::= ({otherwise | t} form*) An example: (case id (10 (foo)) (20 (foo) (bar)) (otherwise (baz))) The expressions are written using s-expressions as data. But still there is structure in those s-expressions, described by the EBNF syntax of CASE. Every special operator and every macro provides syntax. Since users can write macros themselves, everybody can extend the syntax. On top of s-expressions.
- greydius 11y agoThat is interesting. I've always considered lisp in terms of denotational semantics. In fact, I wrote a toy lisp in which the complete grammar was basically list -> ({symbol | number | string | list}*) and then it was up to the interpreter to decide the meaning of special forms. (I say "basically" because there was also desugaring of '(...) to (quote ...)).