semver: Basics

John D Harrison

2026-01-26

The goal of this vignette is to describe the basic functionality of the semver package.

Introduction

The semver package provides tools and functions for parsing, rendering and operating on semantic version strings. Semantic versioning is a simple set of rules and requirements that dictate how version numbers are assigned and incremented as outlined at https://semver.org.

A basic summary of how semantic versioning operates is given a version number MAJOR.MINOR.PATCH, increment the:

  1. MAJOR version when you make incompatible API changes,
  2. MINOR version when you add functionality in a backwards-compatible manner, and
  3. PATCH version when you make backwards-compatible bug fixes.

Additional labels for pre-release and build metadata are available as extensions to the MAJOR.MINOR.PATCH format.

semver package

The semver package provides a wrapper for the C++14 semantic versioning parser written by Marko Živanović. The project is currently hosted on github. The Rcpp package was used to provide R bindings. Some changes were made on the C++ side as currently CRAN does not accept packages compiling under C++14 (R version 3.4.0 should allow this in future).

Parsing/Rendering semantic versions

parse_version

The parse_version function parses a character vector containing valid semantic versioning strings returning an “svlist” object.

library(semver)
examples <- c("1.0.0", "2.1.3", "1.0.0-alpha", "1.0.0-alpha+1.2", 
              "1.8.2-beta.1.13", "1.8.2-beta.1.10")
sem_versions <- parse_version(examples)
sem_versions
## [1] Maj: 1 Min: 0 Pat: 0
## 
## [2] Maj: 2 Min: 1 Pat: 3
## 
## [3] Maj: 1 Min: 0 Pat: 0 Pre: alpha
## 
## [4] Maj: 1 Min: 0 Pat: 0 Pre: alpha Bld: 1.2
## 
## [5] Maj: 1 Min: 8 Pat: 2 Pre: beta.1.13
## 
## [6] Maj: 1 Min: 8 Pat: 2 Pre: beta.1.10
str(sem_versions)
## List of 6
##  $ :Class 'svptr' <externalptr> 
##  $ :Class 'svptr' <externalptr> 
##  $ :Class 'svptr' <externalptr> 
##  $ :Class 'svptr' <externalptr> 
##  $ :Class 'svptr' <externalptr> 
##  $ :Class 'svptr' <externalptr> 
##  - attr(*, "class")= chr "svlist"

render_version

The render_version function acts on an “svptr”/“svlist” object. It returns an R list/(list of lists) giving the major, minor and patch version as an integer and the prerelease and build version as a charcter

render_version(sem_versions[c(1, 4)])
## [[1]]
## [[1]]$major
## [1] 1
## 
## [[1]]$minor
## [1] 0
## 
## [[1]]$patch
## [1] 0
## 
## [[1]]$prerelease
## [1] ""
## 
## [[1]]$build
## [1] ""
## 
## 
## [[2]]
## [[2]]$major
## [1] 1
## 
## [[2]]$minor
## [1] 0
## 
## [[2]]$patch
## [1] 0
## 
## [[2]]$prerelease
## [1] "alpha"
## 
## [[2]]$build
## [1] "1.2"
render_version(sem_versions[[5]])
## $major
## [1] 1
## 
## $minor
## [1] 8
## 
## $patch
## [1] 2
## 
## $prerelease
## [1] "beta.1.13"
## 
## $build
## [1] ""
str(render_version(sem_versions[[5]]))
## List of 5
##  $ major     : int 1
##  $ minor     : int 8
##  $ patch     : int 2
##  $ prerelease: chr "beta.1.13"
##  $ build     : chr ""

Comparing versions

The parse_version function returns a list of svptr objects. These svptr objects represent the semantic versions. We can do comparisons like:

svptr Ops

sem_versions[[1]] <= sem_versions[[5]]
## [1] TRUE
sem_versions[[1]] > sem_versions[[5]]
## [1] FALSE
# compare example 5, 6 (pre-release ordering matters)
sem_versions[[5]] > sem_versions[[6]]
## [1] TRUE
# compare example 3, 4 (build order does not matter)
sem_versions[[3]] == sem_versions[[4]]
## [1] TRUE

Summary of svlist objects

You can get the min, max and range of the versions

min(sem_versions)
## Maj: 1 Min: 0 Pat: 0 Pre: alpha
max(sem_versions)
## Maj: 2 Min: 1 Pat: 3
range(sem_versions)
## [1] Maj: 1 Min: 0 Pat: 0 Pre: alpha
## 
## [2] Maj: 2 Min: 1 Pat: 3

Sort, Order and rank an svlist

You can sort, order and rank the versions:

sort(sem_versions)
## [1] Maj: 1 Min: 0 Pat: 0 Pre: alpha
## 
## [2] Maj: 1 Min: 0 Pat: 0 Pre: alpha Bld: 1.2
## 
## [3] Maj: 1 Min: 0 Pat: 0
## 
## [4] Maj: 1 Min: 8 Pat: 2 Pre: beta.1.10
## 
## [5] Maj: 1 Min: 8 Pat: 2 Pre: beta.1.13
## 
## [6] Maj: 2 Min: 1 Pat: 3
order(sem_versions)
## [1] 3 4 1 6 5 2
rank(sem_versions)
## [1] 3.0 6.0 1.5 1.5 5.0 4.0

Ops on svlist

You can also compare “svlist” objects. If the lengths of the two lists are unequal recycling occurs:

sem_versions > sem_versions[1]
## [1] FALSE  TRUE FALSE FALSE  TRUE  TRUE

Compare to character strings

Sometimes it can be useful to compare a parsed vector of semantic versions to a character string:

sem_versions > "1.1.0-beta"
## [1] FALSE  TRUE FALSE FALSE  TRUE  TRUE
sem_versions[sem_versions > "1.1.0-beta"]
## [1] Maj: 2 Min: 1 Pat: 3
## 
## [2] Maj: 1 Min: 8 Pat: 2 Pre: beta.1.13
## 
## [3] Maj: 1 Min: 8 Pat: 2 Pre: beta.1.10

Updating versions

If you want to change or ammend the major, minor, patch, prerelease or build fields the semver package provides a number of methods to achieve this.

set_version

The set_version method operates on svptr and svlist classes. It simply changes the indicated field to the value given. Other fields in the version are unaffected.

svptr

For the svptr class the set_version method takes a character string argument field which indicates which field (major, minor etc.) to change. The value argument is an integer scalar when field is major, minor or patch and a character string when prerelease or build.

library(semver)
examples <- c("1.0.0", "2.1.3", "1.0.0-alpha", "1.0.0-alpha+1.2", 
              "1.8.2-beta.1.13", "1.8.2-beta.1.10")
sem_versions <- parse_version(examples)
set_version(sem_versions[[1]], "major", 2L)
## Maj: 2 Min: 0 Pat: 0
set_version(sem_versions[[1]], "minor", 1L)
## Maj: 1 Min: 1 Pat: 0
set_version(sem_versions[[1]], "patch", 1L)
## Maj: 1 Min: 0 Pat: 1
set_version(sem_versions[[4]], "prerelease", "beta")
## Maj: 1 Min: 0 Pat: 0 Pre: beta Bld: 1.2
set_version(sem_versions[[4]], "build", "bld1a")
## Maj: 1 Min: 0 Pat: 0 Pre: alpha Bld: bld1a

Note that changing a field with the set_version method does not change any other field.

Dollar assignment

As syntactic sugar for assigning using set_version there is a dollar assignment method for svptr classes so the following are equivalent waysto assign fields:

sem_versions[[1]] <- set_version(sem_versions[[1]], "major", 3L)
sem_versions[[1]]
## Maj: 3 Min: 0 Pat: 0
# Syntactic sugar
sem_versions[[1]]$minor <- 2L
sem_versions[[1]]
## Maj: 3 Min: 2 Pat: 0

svlist

For svlist classes the set_version method expects a character vector for the field argument. The value argument is expected to be a list with integer and character elements assigning to (major, minor, patch)/(prerelease, build) fields respectively. If either the length of the field or values argeument is shorter than the number of elements in the svlist then recycling occurs.

examples <- c("1.0.0", "1.8.2-beta.1.10", "2.4.6-8")
sem_versions <- parse_version(examples)
# recycling on the field argument
set_version(sem_versions, "major", list(2L, 4L, 6L))
## [1] Maj: 2 Min: 0 Pat: 0
## 
## [2] Maj: 4 Min: 8 Pat: 2 Pre: beta.1.10
## 
## [3] Maj: 6 Min: 4 Pat: 6 Pre: 8
# recycling on the value argument
set_version(sem_versions, c("major", "minor", "patch"), list(7L))
## [1] Maj: 7 Min: 0 Pat: 0
## 
## [2] Maj: 1 Min: 7 Pat: 2 Pre: beta.1.10
## 
## [3] Maj: 2 Min: 4 Pat: 7 Pre: 8
# assigning integer and character values
set_version(sem_versions, c("prerelease", "minor", "build"), 
            list("alpha", 3L, "build1.12"))
## [1] Maj: 1 Min: 0 Pat: 0 Pre: alpha
## 
## [2] Maj: 1 Min: 3 Pat: 2 Pre: beta.1.10
## 
## [3] Maj: 2 Min: 4 Pat: 6 Pre: 8 Bld: build1.12

reset_version

The reset_version method operates on svptr and svlist classes. It changes the indicated field to the value given. Fields with lower precedence are set to default values:

MAJOR(0L) > MINOR (0L) > PATCH (0L) > PRERELEASE ("") > BUILD ("")

svptr

The reset_version method for svptr classes operates similarly to the set_version method with fields of lower precedence being set to default values:

examples <- c("1.8.2-beta.1.10+somebuild", "2.4.6-8")
sem_versions <- parse_version(examples)
reset_version(sem_versions[[1]], "major", 2L)
## Maj: 2 Min: 0 Pat: 0
reset_version(sem_versions[[1]], "minor", 3L)
## Maj: 1 Min: 3 Pat: 0
reset_version(sem_versions[[1]], "patch", 4L)
## Maj: 1 Min: 8 Pat: 4
reset_version(sem_versions[[1]], "prerelease", "gamma")
## Maj: 1 Min: 8 Pat: 2 Pre: gamma
reset_version(sem_versions[[1]], "build", "superbuild")
## Maj: 1 Min: 8 Pat: 2 Pre: beta.1.10 Bld: superbuild

svlist

The reset_version method for svlist classes operates similarly to the set_version method with fields of lower precedence being set to default values. Again recycling of elements occur if the length of the field/value argument is shorter than the number of elements in the svlist:

examples <- c("1.8.2-beta.1.10+somebuild", "2.4.6-8")
sem_versions <- parse_version(examples)
# recycling on both arguments
reset_version(sem_versions, "major", list(3L))
## [1] Maj: 3 Min: 0 Pat: 0
## 
## [2] Maj: 3 Min: 0 Pat: 0
# recycling on field argument
reset_version(sem_versions, "minor", list(3L, 4L))
## [1] Maj: 1 Min: 3 Pat: 0
## 
## [2] Maj: 2 Min: 4 Pat: 0
# recycling on value argument
reset_version(sem_versions, c("major", "patch"), list(4L))
## [1] Maj: 4 Min: 0 Pat: 0
## 
## [2] Maj: 2 Min: 4 Pat: 4
# assigning integer and character fields
reset_version(sem_versions, c("prerelease", "minor"), list("zeta", 7L))
## [1] Maj: 1 Min: 8 Pat: 2 Pre: zeta
## 
## [2] Maj: 2 Min: 7 Pat: 0

increment_version

The increment_version method operates on svptr and svlist classes. It increments the given field with the provided value. Fields of lower precedence are set to default value.

  1. Only major, minor and patch field can be incremented

  2. To decrement a field provide a negative integer as the value argument

svptr

The increment_version method for svptr classes increments the chosen field with the given value with fields of lower precedence being set to default values:

examples <- c("1.8.2-beta.1.10+somebuild", "2.4.6-8")
sem_versions <- parse_version(examples)
# incrementing versions
increment_version(sem_versions[[1]], "major", 1L)
## Maj: 2 Min: 0 Pat: 0
increment_version(sem_versions[[1]], "minor", 2L)
## Maj: 1 Min: 10 Pat: 0
increment_version(sem_versions[[1]], "patch", 3L)
## Maj: 1 Min: 8 Pat: 5
# decrementing versions
increment_version(sem_versions[[1]], "major", -1L)
## Maj: 0 Min: 0 Pat: 0
increment_version(sem_versions[[1]], "minor", -2L)
## Maj: 1 Min: 6 Pat: 0
increment_version(sem_versions[[1]], "patch", -2L)
## Maj: 1 Min: 8 Pat: 0

svlist

The increment_version method for svlist classes takes a character vector as argument field and an integer vector as argument value. Recycling occurs as for set_version/reset_version methods:

examples <- c("1.8.2-beta.1.10+somebuild", "2.4.6-8")
sem_versions <- parse_version(examples)
## Incrementing
# recycling on both arguments
increment_version(sem_versions, "major", 3L)
## [1] Maj: 4 Min: 0 Pat: 0
## 
## [2] Maj: 5 Min: 0 Pat: 0
# recycling on field argument
increment_version(sem_versions, "minor", c(3L, 4L))
## [1] Maj: 1 Min: 11 Pat: 0
## 
## [2] Maj: 2 Min: 8 Pat: 0
# recycling on value argument
increment_version(sem_versions, c("major", "patch"), 4L)
## [1] Maj: 5 Min: 0 Pat: 0
## 
## [2] Maj: 2 Min: 4 Pat: 10
## Decrementing
# recycling on both arguments
increment_version(sem_versions, "major", -1L)
## [1] Maj: 0 Min: 0 Pat: 0
## 
## [2] Maj: 1 Min: 0 Pat: 0
# recycling on field argument
increment_version(sem_versions, "minor", c(-3L, -4L))
## [1] Maj: 1 Min: 5 Pat: 0
## 
## [2] Maj: 2 Min: 0 Pat: 0
# recycling on value argument
increment_version(sem_versions, c("minor"), -4L)
## [1] Maj: 1 Min: 4 Pat: 0
## 
## [2] Maj: 2 Min: 0 Pat: 0

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