Hello! Since there are a few pitfalls to updating eggs to work with the new Chicken 4.6.2, I've decided to draw up a quick list of pitfalls I noticed.
If you're just using the regex API or the regex API with a few irregex things, usually all you need is to add (needs regex) to your egg's meta file and you're done (but read on!). If you are only using the irregex API and don't want to drag in another dependency just to keep older Chickens happy, here's a way to depend on just irregex in either old or new Chicken. Add the following to your .setup file: (define regex-version (if (version>=? (chicken-version) "4.6.2") 'total-irregex 'irregex-through-regex)) and alter your compilation line to read something like this: (compile -s -D ,regex-version my-egg.scm -j my-egg) In your egg's file, where you would previously use this idiom: (require-library regex) ; or (use regex) for the lazy & sloppy (import irregex) you can now replace it with this block (you can delete emulation of procedures you are sure you aren't using): (cond-expand (total-irregex (use irregex)) (else (require-library regex) (import (rename irregex (irregex-match-start irregex-match-start-index) (irregex-match-end irregex-match-end-index))) (define irregex-num-submatches irregex-submatches) (define irregex-match-num-submatches irregex-submatches) (define (irregex-match-valid-index? m i) (and (irregex-match-start-index m i) #t)) (define (maybe-string->sre obj) (if (string? obj) (string->sre obj) obj)))) We need to do this because the irregex-match-{start,end} procedures have been suffixed "-index". But be careful! They also have slightly changed semantics. If you pass an index of a submatch which did not get matched, irrgex-match-start-index will throw an exception. You first need to test whether it matched. That's what irregex-match-valid-index? is for, which we simulate in older Chickens by simply attempting to fetch the start index and checking whether it succeeded. We also define irregex-[match-]num-submatches as irregex-submatches. The old procedure accepted both match objects and irregex objects, while the new procedures are more consistent with the rest of the API and only accept their corresponding types. The maybe-string->sre is just copied from the irregex-core.scm file. One last pitfall to take care of is the fact that the new irregex has a few new procedures. For example, the old Chicken's irregex simply didn't have the chunked matching API at all. Here's a list of things that are unavailable in older Chickens: irregex-extract irregex-fold/chunked irregex-match? irregex-match-end-index (but see emulation code above) irregex-match-end-chunk irregex-match-names irregex-match-start-index (but see emulation code above) irregex-match-start-chunk irregex-match-subchunk irregex-match-valid-index? (but see emulation code above) irregex-match/chunked irregex-num-submatches (but see emulation code above) irregex-opt irregex-quote irregex-split make-irregex-chunker maybe-string->sre (but see emulation code above) Cheers, Peter -- http://sjamaan.ath.cx -- "The process of preparing programs for a digital computer is especially attractive, not only because it can be economically and scientifically rewarding, but also because it can be an aesthetic experience much like composing poetry or music." -- Donald Knuth _______________________________________________ Chicken-users mailing list Chicken-users@nongnu.org http://lists.nongnu.org/mailman/listinfo/chicken-users