Ah ok, Thanks for the information. For non negative integers I suspected that.
Le dim. 16 juin 2024 à 20:05, Waldek Hebisch <[email protected]> a écrit : > > On Sun, Jun 16, 2024 at 07:42:54PM +0200, Grégory Vanuxem wrote: > > Hello, > > > > Have you ever tried the function in object? > > For negative integers it returns strange integers: > > > > (1) -> parse_integer("-4")$ScanningUtilities > > > > (1) - 26 > > Type: > > Integer > > (2) -> parse_integer("4")$ScanningUtilities > > > > (2) 4 > > Type: > > Integer > > 'parse_integer' is intended for nonnegative integers. Adding > handling for sign would be relatively easy. OTOH 'parse_integer' > assumes that it is given valid number (string of digits) and > will produce nonsense on invalid imput. To reiterate: idea > of 'parse_integer' is that lexical analyser verified correctness > of input and now task is to convert _valid_ input to a number. > For other uses we would need to add extra checks to > 'parse_integer'. > > > Apparently it is only used with 'ScanArabic' in outform.spad so it > > does not have a lot of consequences. > > Note that 'ScanArabic' can only produce positive integers, so > valid input to 'ScanArabic' is also valid input to 'parse_integer' > > > Grepping src/algebra: > > > > src/algebra/outform.spad: ScanArabic s == > > qcoerce(parse_integer(s)$ScanningUtilities) > > > > By the way, there exists the Lisp function parse-integer, although not > > very satisfactory in the FriCAS sense. > > > > It may not be what I have thought also. > > 'parse_integer' is intended to be part of new FriCAS compiler and > interpreter. For large integers 'parse_integer' may be significantly > faster than Lisp 'PARSE-INTEGER', in fact slowness of 'PARSE-INTEGER' > was main motivation to develop 'parse_integer'. > > -- > Waldek Hebisch > > -- > You received this message because you are subscribed to the Google Groups > "FriCAS - computer algebra system" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/fricas-devel/Zm8pYbppoFIeJH4P%40fricas.org. -- You received this message because you are subscribed to the Google Groups "FriCAS - computer algebra system" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/fricas-devel/CAHnU2dbFzQ0hvON%3D1ri4RNZWZ2PztFY%2BLJa_aC%2BqOiTxt-12rg%40mail.gmail.com.
