Known incompatibilities with Teyjus

This file tries to summarize known incompatibilities between Elpi and Teyjus.

Semantics

; is not a built-in and behaves differently wrt !
unification problems outside the pattern fragment are not delayed unless one passes the (deprecated) -delay-problems-outside-pattern-fragment flag to elpi
integers are 31 bits (25 bits in Teyjus); etc for floats ...

Since Elpi 1.15 the default parser does not support the infix directive
No syntax for negative numbers: ~ 2 is the unary minus applied to 2, not the number -2. If you want to write -2, just write -2 with no space in between.
No support for \OCTAL \OCTALOCTALOCTAL \xHEX \xHEXHEX
Strings must not contain newlines; instead \n, \b, \t, \r, \\, \", \', "" are recognized.
Non-associative infix/prefix/postfix behave like their associative counterparts. In particular, if @@ and @@@ are two prefix operators with precedence @@ > @@@ then (@@ @@@ @@ @@@ a) is parsed nevertheless
Elements of lists are parsed at level 120, that is the first level used in lp-syntax.elpi after 110, the level of ,.
i<, r+, etc. are polymorphic
No support for x :: : type l and x = : type y.
If a file ends (without eol) inside a comment, the parser ignores the comment (in place of returning an error). The same happens if the query is not . terminated.
No beta-redexes in the source code.

Module signatures are ignored.
Elpi accumulates each file once; Teyjus does it multiple times, that is always bad (all clauses are duplicated and tried multiple times, that is rarely the expected behavior).
Elpi understands relative paths as in accumulate "../foo": resolution of relative paths is done according to the path of the accumulating file first or, if it fails, according to the TJPATH.
No support for import.