Gentoo Archives: gentoo-dev

From: Ulrich Mueller <ulm@g.o>
To: gentoo-dev@l.g.o
Subject: [gentoo-dev] RFD: Replacement for versionator.eclass in PMS (for EAPI 7?)
Date: Sat, 28 Nov 2015 21:14:57
Message-Id: 22106.6463.805834.391338@a1i15.kph.uni-mainz.de
1 As you may know, we intend to move the functionality of
2 versionator.eclass to the package manager, possibly in EAPI 7.
3 The following is what mgorny and myself have come up with, see
4 bug 482170 [1], especially comments 15 and 16 there.
5
6 Currently there are 15 functions defined in that eclass, and we
7 believe that it will not be feasible to implement all of them.
8 However, several of the functions are similar to each other and can
9 be combined. Two of them, namely get_version_component_range() and
10 replace_version_separator(), account for the vast majority of what
11 is used by ebuilds.
12
13 We therefore think that the following three functions would be
14 sufficient to cover all ebuilds' needs:
15
16
17 version_test [VERSION1] OP VERSION2
18 ===================================
19
20 This comes in a two and a three argument form. Syntax is based on
21 test(1) (therefore the name).
22
23 - Compares VERSION1 with VERSION2, using the usual PMS version
24 comparison algorithm.
25
26 - OP can be one of -eq, -ne, -lt, -le, -gt, -ge, i.e. the binary
27 arithmetic operators from test(1). (We avoid C style <, >, etc.
28 because they suffer from quoting issues.)
29
30 - Both VERSION1 and VERSION2 must be valid Gentoo versions.
31
32 - VERSION1 can be omitted and defaults to PVR.
33
34 version_cut RANGE [VERSION]
35 ===========================
36
37 Since this (and the next) function is intended to aid with conversion
38 from Gentoo versions to foreign versions and vice versa, it is neither
39 required that VERSION is a valid Gentoo version, nor will the function
40 use Gentoo version syntax for splitting. Instead, the following simple
41 rules will be applied:
42
43 A version string is composed of one or more version components,
44 delimited by (possibly empty) version separators. Each component is a
45 sequence made purely of letters [A-Za-z] or purely of digits [0-9].
46 Separators are sequences of other characters [^A-Za-z0-9]. A version
47 string must start and end with a component (if it doesn't, an empty
48 first or last component is implied).
49
50 For example, the version:
51
52 1.2.3b_alpha4
53
54 would be split into (c being component indexes, s separator indexes):
55
56 1 . 2 . 3 '' b _ alpha '' 4
57
58 ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
59 c1 s1 c2 s2 c3 s3 c4 s4 c5 s5 c6
60
61 Now to the version_cut() function itself:
62
63 - Extracts a part of the version string, containing components from
64 the specified RANGE along with separators that are inbetween.
65
66 - RANGE is START[-[END]], i.e. START for one index, START-END for a
67 range of indexes, or START- for up to the last component.
68
69 - All separators contained between the requested version components
70 are included; separators preceding and following them are not.
71 For example, "version_cut 2-4 1.2.3b_alpha4" would return "2.3b".
72
73 - VERSION can be omitted and defaults to PV.
74
75 version_replace_separator RANGE REPL [RANGE REPL...] [VERSION]
76 ==============================================================
77
78 Especially for this function's name, bikeshedding is still needed.
79 The name should be reasonably short, as it will be used in global
80 scope command substitution.
81
82 Version components and separators are determined as for the
83 version_cut() function.
84
85 - Replaces version separators by index.
86
87 - RANGE is START[-[END]], i.e. START for one index, START-END for a
88 range of indexes, or START- for up to the last separator.
89
90 - If RANGE includes empty separators, they are replaced as well.
91 For example, "replace_version_sep 3 - 1.2.3b" outputs "1.2.3-b".
92
93 - REPL is a replacement string. It can be any string, and will be
94 repeated for each replaced separator.
95
96 - Multiple pairs of RANGE and REPL can be specified. For example,
97 "replace_version_sep 1 - 3 '~' 1.2.3b" would output "1-2.3~b".
98
99 - VERSION can be omitted and defaults to PV.
100
101 - It is not yet entirely clear what should be done in case of
102 overlapping ranges. It could be an error, or the last replacement
103 could win. Similarly, what should be done if there are less
104 separators than specified? (versionator.eclass silently ignores the
105 surplus ones.)
106
107
108 Questions:
109 1. Will these three functions be sufficient, or have we overlooked
110 anything important?
111 2. Are the proposed specifications sane?
112 3. Some bikeshedding for the names, especially for the name of the
113 version_replace_separator() function is needed.
114
115 Ulrich
116
117
118 [1] https://bugs.gentoo.org/show_bug.cgi?id=482170

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