src/core/packages/datastructures.sgl

1;;; Generic data-structure libraries.

2;;;

3;;; tllist is a header-only typed linked list. It is in this channel because

4;;; fcft and foot both `dependency('tllist')`, and foot's fallback for it is a

5;;; `[wrap-git]` subproject pointing at a live git URL -- which cannot resolve

6;;; inside a build sandbox, so a real package is not optional.

7(define-library (core packages datastructures)

8 (import (sigil core)

9 (core build-environments)

10 (sigil env package)

11 (sigil build external))

12 (export tllist)

13 (begin

14 ;; TLLIST IS HEADER-ONLY AND IS STILL DECLARED AS A `dependencies:` ENTRY

15 ;; BY ITS CONSUMERS, WHICH PUTS A BUILD-TIME-ONLY LIBRARY IN THEIR RUNTIME

16 ;; CLOSURE. That is not sloppiness; the channel has no other category for

17 ;; it, and the reason is worth knowing before someone "fixes" it.

18 ;;

19 ;; `build-inputs:` contributes the input's `bin/` to PATH and nothing else

20 ;; -- no `-I`, no `-L`, no `PKG_CONFIG_PATH`. It can additionally carry a

21 ;; package's own `search-paths:` exports, so a header-only library CAN

22 ;; reach a build as a build input by exporting `CPATH`.

23 ;;

24 ;; What it cannot do is be found by PKG-CONFIG. `PKG_CONFIG_PATH` is

25 ;; composed by the builder from DEPENDENCIES only, and it is builder-owned,

26 ;; so a package may not export it -- that is refused by name. fcft and

27 ;; foot both locate this library with `dependency('tllist')`, which is a

28 ;; pkg-config lookup, so it has to be a dependency.

29 ;;

30 ;; So: THERE IS NO "BUILD-TIME LIBRARY" CATEGORY HERE. A package that is

31 ;; discovered through pkg-config is a runtime dependency by construction,

32 ;; whether or not anything of it survives into the binary. For a

33 ;; header-only library nothing does.

34

35 ;; INSTALLED BY HAND RATHER THAN BY MESON, DELIBERATELY.

36 ;;

37 ;; tllist is one header and a `.pc` file. Its meson.build does exactly

38 ;; two things when it is not a subproject: `install_headers('tllist.h')`

39 ;; and `pkg.generate(...)`. Running a full meson configure to copy one

40 ;; header would put meson, samurai and python on the critical path of a

41 ;; package that needs none of them -- and this package was written before

42 ;; meson had been proven in this channel at all, which is the actual

43 ;; reason: it removes a dependency from the ordering, not just from the

44 ;; build.

45 ;;

46 ;; The `.pc` is hand-written to match what meson's pkgconfig module would

47 ;; have emitted. NOTE THE ABSENCE OF `${prefix}`-STYLE VARIABLES: a

48 ;; pkg-config file would normally define `prefix=` and refer to it, but

49 ;; `${...}` inside a run-phase argument is intercepted by SIGIL's

50 ;; interpolation, not by the shell or by pkg-config, and any name that is

51 ;; not `out` or a declared input is an error at evaluation time. Absolute

52 ;; paths are what the rest of this channel bakes anyway.

53 (define tllist

54 (package

55 name: "tllist"

56 version: "1.1.0"

57 source: (external-source

58 location: "https://codeberg.org/dnkl/tllist/releases/download/1.1.0/tllist-1.1.0.tar.gz"

59 sha256: "a1f0ce0dc4fcb4ce59c37202a1d914c853a8bd2d7c5d57d623b15a8dd9778767")

60 buildenv: core-buildenv

61 phases: (list

62 (external-phase

63 kind: 'run

64 args: (list "sh" "-c"

65 (string-append

66 "set -eu\n"

67 "d=\"$(dirname \"$PWD\")/install-root\"\n"

68 "mkdir -p \"$d${out}/include\" \"$d${out}/lib/pkgconfig\"\n"

69 ;; `install -m` rather than `cp`, so the installed mode is a

70 ;; function of the derivation and not of the

71 ;; ambient umask.

72 "install -m 644 tllist.h \"$d${out}/include/tllist.h\"\n"

73 "cat > \"$d${out}/lib/pkgconfig/tllist.pc\" <<'PC'\n"

74 "Name: tllist\n"

75 "Description: A C header file only implementation of a typed linked list\n"

76 "Version: 1.1.0\n"

77 "Cflags: -I${out}/include\n"

78 "PC\n"

79 ;; Prove the artifact rather than trust the copy:

80 ;; the header must be there AND pkg-config must

81 ;; be able to answer a query about it, which is

82 ;; what every consumer will actually do.

83 "test -f \"$d${out}/include/tllist.h\"\n"

84 "PKG_CONFIG_PATH=\"$d${out}/lib/pkgconfig\" pkg-config --exists tllist\n"

85 "PKG_CONFIG_PATH=\"$d${out}/lib/pkgconfig\" pkg-config --modversion tllist\n"

86 "echo TLLIST-INSTALLED\n"))))))))