People,
I have the following beginner question on declaring a category
(in FriCAS-1.1.5):
----------------------------------------- t1.spad ------------
Set1(): Category ==
Join(Type, CoercibleTo OutputForm) with
"=" : (\$, \$) -> Boolean
--------------------------------------------------------------
This is copied from the book Chapter 12.6, with `SetCategory' renamed
to `Set1' (to prevent possible overlap with the Axiom library).
Then,
)compile t1
produces the report
-----------------------------------------------------------------
Compiling FriCAS source code from file
/home/mechvel/ghc/axiomInterface/fromA-aim/t1.spad using old
system compiler.
******** Boot Syntax Error detected ********
The prior line was:
1> Join(Type, CoercibleTo OutputForm) with
The current line is:
2> "=" : (\$, \$) -> Boolean
^
The number of valid tokens is 1.
The prior token was #S(TOKEN :SYMBOL |(| :TYPE KEYWORD :NONBLANK NIL)
The current token is #S(TOKEN :SYMBOL |\\| :TYPE KEYWORD :NONBLANK T)
-----------------------------------------------------------------
Generally, it is often difficult to understand the compiler messages,
subtle Lisp denotations, etc.
Replacing \$ with $ does not help
(what does this `\' mean here?).
I failed to define the first example of some simple category.
My nearest aim is to define
Lexeme : Type := String -- renaming a type (?)
DParse(): Category ==
Join(Type, CoercibleTo OutputForm) with
dParseLexemes : List Lexeme -> Product($, List Lexeme)
(`$' denotes _this domain_)
and to add (and implement) the instances of DParse for Integer
and for UnivariatePolynomial(R, v)
where R has CommutativeRing, v a variable (Symbol ?).
But so far, I failed to define just any category.
Thank you in advance for explanation,
------
Sergei
[email protected]
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