------------------------------ t.spad -----------------------------
)abbrev package FOO Foo
Foo() : with
f : () -> SExpression
==
add
f() ==
e1 := convert("ab" :: Symbol) $SExpression
e2 := convert("cd" :: Symbol) $SExpression
convert([e1, e2]) $SExpression
-------------------------------------------------------------------
Thank you. That's much easier to give an answer to (although (1) I don't
see an error message for THIS program and (2) that program actually
compiles and thus doesn't show the actual problem you have).
Sorry, I am quite picky here, but you should think about the time that
others spend in trying to help you. If it is too much, you might simply
get no answer.
1. Why in the last line the comipler insists on "()" ?
Without the parens, I get the error below.
Because, in fact, the compiler transforms the last line into something like
(convert$SExpression) [e1, e2]
(you could even write this literally like this). If you remove the
parens then it's equivalent to
convert( construct(e1,e2)$SExpression )
and not the intended
convert(construct(e1,e2))$SExpression
2. Is this natural that the first line of
("ab" :: Symbol) :: SExpression
is not compiled?
What makes you believe that it is not compiled?
3. As there are `coerce' and `::', why does Spad need `convert' ?
http://axiom-developer.org/axiom-website/hyperdoc/axbook/section-2.7.xhtml
In Aldor there even isn't "convert".
http://www.aldor.org/docs/HTML/chap11.html#7
4. I define coerce(s : String) : SExpression ==
convert(s :: Symbol) $SExpression
and use "ab" :: SExpression.
Is this a good way out?
Read the axiom book above of what this means. In fact, if you do not
export this coerce function, then it doesn't mean anything outside of
your domain/package, i.e. you can do whatever you find appropriate.
3. Sometimes `g :: OutputForm' does not work in Spad, while
coerce(g) :: OutputForm does work.
What is the difference?
Too few information. I don't want to guess. The only thing I can say
here is that without context it is not clear where the explicitly
written "coerce" comes from.
Before you pose your question again, learn about the difference of
foo(..)$P
foo(..)::T
foo(..)@T
Perhaps then you can answer the question already yourself.
Hope that gives you a few hints.
Ralf
===================================================================
(1) -> )co foo.spad
Compiling FriCAS source code from file
/home/hemmecke/scratch/spad/foo.spad using old system compiler.
FOO abbreviates package Foo
------------------------------------------------------------------------
initializing NRLIB FOO for Foo
compiling into NRLIB FOO
compiling exported f : () -> SExpression
****** comp fails at level 5 with expression: ******
error in function f
(SEQ
(LET |e1|
((|elt| (|SExpression|) |convert|) (|::| "ab" (|Symbol|))))
(LET |e2|
((|elt| (|SExpression|) |convert|) (|::| "cd" (|Symbol|))))
(|exit| 1 (|convert| ((|elt| (|SExpression|) |construct|) |e1| |e2|))))
****** level 5 ******
$x:= (construct e1 e2)
$m:= (SExpression)
$f:=
((((|e2| #) (|e1| #) (|$Information| #) (|f| #) ...)))
>> Apparent user error:
Cannot coerce (LIST e1 e2)
of mode (List (SExpression))
to mode (SExpression)
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