Hi Lduo, On Sun, 15 Nov 2020 at 17:33, Ludovic Courtès <l...@gnu.org> wrote:
> That said, this message is about a possible implementation of package > parameters, so here we go. :-) Cool! > To me the requirements for package parameters are: > > 1. it must be possible to discover them and choose them from the UI; > > 2. they must contain on-line internationalized documentation such that > the UI can list a package’s parameters and their type; Except ’boolean’, which kind of type do you have in mind? Aside that you did not find examples of packages requiring parameters. ;-) The answer leads to your point #4. > 3. the chosen parameters when installing a package in a profile must > be preserved; You mean track the parameters with ’properties’ in <profile>/manifest, right? > 4. it must be possible to enumerate all the possible values of a > parameter, and thus to build the Cartesian product of all the > possible parameter combinations of a package (or of a package > graph!), so we can test those combinations as much as possible. The values of the option are therefore known at package time, right? However, this implies restricted possibility for the type, right? > Subject: [PATCH 1/4] DRAFT Add (guix parameters). > > DRAFT: Missing tests & doc. > > * guix/parameters.scm: New file. > * Makefile.am (MODULES): Add it. > --- [...] > diff --git a/guix/parameters.scm b/guix/parameters.scm > + > +;; Type of a package parameter. > +(define-record-type* <parameter-type> parameter-type > + make-parameter-type > + parameter-type? > + (name parameter-type-name) ;debugging purposes only! > + (string->value parameter-type-string->value) > + (value->string parameter-type-value->string) > + (universe parameter-type-universe)) > + > +(define boolean > + ;; The Boolean parameter type. > + (parameter-type (name 'boolean) > + (universe '(#true #false)) > + (value->string > + (match-lambda > + (#f "false") > + (#t "true"))) > + (string->value > + (lambda (str) > + (cond ((string-ci=? str "true") > + #t) > + ((string-ci=? str "false") > + #f) > + (else > + (raise (condition > + (&message (message "wrong > value")))))))))) The types will be “hard-coded“ here, right? Boolean being the simplest example and imagination just needs to be released, right? :-) > Subject: [PATCH 2/4] DRAFT transformations: Add '--with-parameter'. > > DRAFT: Missing tests & doc. > > * guix/transformations.scm (evaluate-parameter-specs) > (transform-package-parameters): New procedures. > (%transformations, %transformation-options): Add 'with-parameter'. > --- > guix/transformations.scm | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > > diff --git a/guix/transformations.scm b/guix/transformations.scm [...] > +(define (evaluate-parameter-specs specs proc) > + "Parse SPECS, a list of strings like \"bitlbee=purple=true\", and return a > +list of spec/procedure pairs, where (PROC PACKAGE PARAMETER VALUE) is called > +to return the replacement package. Raise an error if an element of SPECS > uses > +invalid syntax, or if a package it refers to could not be found." > + (map (lambda (spec) > + (match (string-tokenize spec %not-equal) > + ((spec name value) > + (define (replace old) > + (proc old name value)) > + > + (cons spec replace)) > + (_ > + (raise > + (formatted-message > + (G_ "invalid package parameter specification: ~s") > + spec))))) > + specs)) Here ’proc’ could be anything, right? But then… > +(define (transform-package-parameters replacement-specs) > + "Return a procedure that, when passed a package, replaces its direct > +dependencies according to REPLACEMENT-SPECS. REPLACEMENT-SPECS is a list of > +strings like \"guile-next=stable-3.0\" meaning that packages are built using > +'guile-next' from the latest commit on its 'stable-3.0' branch." > + (define (replace old name value) > + (set-package-parameter-value old name value)) > + > + (let* ((replacements (evaluate-parameter-specs replacement-specs > + replace)) > + (rewrite (package-input-rewriting/spec replacements))) > + (lambda (obj) > + (if (package? obj) > + (rewrite obj) > + obj)))) … it is ’set-package-parameter-value’. It is not clear in my mind. Does this constrain the hypothetical types? Cheers, simon
