To my
>> Has the library a function that breaks a string to the Spad lexemes?
>> In DoCon, I use the Haskell lexemes for this and the corresponding
>> library function for breaking to lexemes (and this also defines what
>> is a lexeme).
Waldek Hebish wrote
> You may with to look at Lisp function READ-FROM-STRING. One can
> use it to convert string into arbitrary Lisp data. In particular
>
> (1) -> READ_-FROM_-STRING("(|powerProduct| 4 1 2)")$Lisp
>
> (1) (powerProduct 4 1 2) : SExpression
> that is you may easily get list of whatever entries you need.
> The return type of calls to Lisp function is SExpression, but one
> can convert it to apropriate type.
1. I guess, `$Lisp' is a package calling.
And Browse - Lisp - packages reports that there is no package
named Lisp.
2. READ_-FROM_-STRING("cons (I 23) cons (I 12) NIL")$Lisp
yields
CONS Type: SExpression
But how to part the remaining lexemes?
Rather the result needs to be
[CONS, "(I 23) cons (I 12) NIL"]
Type: Product(SExpression, String).
Am I missing something?
3. It is desirable to have a _function from the standard Axiom library_
(hence, and a documented one). Because the language of Spad/Axiom is
somehow defined (?), fixed, and announced. A lexeme notion is a part of
the syntax, each programming language defines what is its lexeme.
Hence it is reasonable to provide a function in the standard library
which breaks a string into lexemes.
If f == READ_-FROM_-STRING is not documented as standard, then f is
not mandatory. Then the developers may write for the next FriCAS release
"We changed the implementation: removed such and such lexer ... and
READ_-FROM_-STRING is no longer valid".
And the applications based on f will break and will need to change
their code.
In this sense, how reliable are READ_-FROM_-STRING, and other items
from the Lisp package?
Where to find the description for these items?
Thanks,
------
Sergei
[email protected]
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