go-gem-version

go-gem-version is a library for parsing RubyGems versions and version constraints, and verifying versions against a set of constraints. go-gem-version can sort a collection of versions properly, handles prerelease versions, etc.

Versions used with go-gem-version must follow RubyGems versioning policy.

For more details, see version.rb and requirement.rb.

Usage

Version Parsing and Comparison

See example

v1, _ := gem.NewVersion("1.2.a")
v2, _ := gem.NewVersion("1.2")

// Comparison example. There is also GreaterThan, Equal, and just
// a simple Compare that returns an int allowing easy >=, <=, etc.
if v1.LessThan(v2) {
	fmt.Printf("%s is less than %s", v1, v2)
}

Version Constraints

See example

v, _ := gem.NewVersion("2.1")
c, _ := gem.NewConstraints(">= 1.0, < 1.4 || > 2.0")

if c.Check(v) {
	fmt.Printf("%s satisfies constraints '%s'", v, c)
}

Version Sorting

See example

versionsRaw := []string{"1.1", "0.7.1", "1.4.a", "1.4.a.1", "1.4", "1.4.0.1"}
versions := make([]gem.Version, len(versionsRaw))
for i, raw := range versionsRaw {
	v, _ := gem.NewVersion(raw)
	versions[i] = v
}

// After this, the versions are properly sorted
sort.Sort(gem.Collection(versions))

Pessimistic Operator

• ~> 3.0 := >= 3.0, < 4.0
• ~> 3.0.0 := >= 3.0.0, < 3.1
• ~> 3.5 := >= 3.5, < 4.0
• ~> 3.5.0 := >= 3.5.0, < 3.6
• ~> 3 := >= 3.0, < 4.0

For more details, see here