# API reference Source: https://libtmux.org/en/haskell/latest/reference/ > Modules, data types, constructors, record fields and functions in libtmux for Haskell. Browse the Haskell types and operations for working with tmux. Start with the core objects below, or search for a type or member. LibTmux.Id 1 type [LibTmux.Id](https://libtmux.org/en/haskell/latest/reference/libtmux-id/) module 13 members Distinct session, physical-window and physical-pane IDs. LibTmux.Id — Entity identities 3 functions and constants [SessionId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-t-sessionid/) data type A session's unsigned 32-bit tmux identifier, written with a `$` prefix. Parse with [`parseSessionId`](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-parsesessionid/ "function"); render with [`renderSessionId`](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-rendersessionid/ "function"). [WindowId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-t-windowid/) data type A physical window's identifier, independent of its session links. Parse with [`parseWindowId`](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-parsewindowid/ "function"); render with [`renderWindowId`](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-renderwindowid/ "function"). [PaneId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-t-paneid/) data type A physical pane's identifier, written with a `%` prefix. Parse with [`parsePaneId`](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-parsepaneid/ "function"); render with [`renderPaneId`](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-renderpaneid/ "function"). LibTmux.Id — Parse external values 4 functions and constants [IdError](https://libtmux.org/en/haskell/latest/reference/libtmux-id-t-iderror/) data type 3 members Invalid canonical syntax, entity prefix or native unsigned range. Diagnostics retain at most 64 characters of input. [parseSessionId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-parsesessionid/) function Parse `$0` through `$4294967295`. No whitespace or leading zeroes. [parseWindowId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-parsewindowid/) function Parse a canonical `@number` identifying a physical window. [parsePaneId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-parsepaneid/) function Parse a canonical `%number` identifying a physical pane. LibTmux.Id — Render target text 3 functions and constants [renderSessionId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-rendersessionid/) function Render the session prefix and decimal ID. [renderWindowId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-renderwindowid/) function Render the physical window prefix and decimal ID. [renderPaneId](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-renderpaneid/) function Render the physical pane prefix and decimal ID. LibTmux.Id — Read numeric values 3 functions and constants [sessionIdValue](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-sessionidvalue/) function Read the numeric session ID without narrowing conversion. [windowIdValue](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-windowidvalue/) function Read the numeric physical window ID. [paneIdValue](https://libtmux.org/en/haskell/latest/reference/libtmux-id-v-paneidvalue/) function Read the numeric physical pane ID. LibTmux.Value 1 type [LibTmux.Value](https://libtmux.org/en/haskell/latest/reference/libtmux-value/) module 10 members Positive dimensions and nonnegative contextual indices. LibTmux.Value — Checked types 3 functions and constants [Dimension](https://libtmux.org/en/haskell/latest/reference/libtmux-value-t-dimension/) data type Positive cells, constructed with [`mkDimension`](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-mkdimension/ "function"). Command and field limits are checked separately. Compare dimensions directly or use [`dimensionValue`](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-dimensionvalue/ "function") with an integer literal. [WindowIndex](https://libtmux.org/en/haskell/latest/reference/libtmux-value-t-windowindex/) data type Nonnegative index of a window link within a session, not a physical window ID. Construct with [`mkWindowIndex`](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-mkwindowindex/ "function"); read with [`windowIndexValue`](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-windowindexvalue/ "function"). [PaneIndex](https://libtmux.org/en/haskell/latest/reference/libtmux-value-t-paneindex/) data type Nonnegative pane index within a window, not a pane ID. Construct with [`mkPaneIndex`](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-mkpaneindex/ "function"); read with [`paneIndexValue`](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-paneindexvalue/ "function"). LibTmux.Value — Validate input 4 functions and constants [ValueError](https://libtmux.org/en/haskell/latest/reference/libtmux-value-t-valueerror/) data type 2 members A scalar outside its mathematical domain. [mkDimension](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-mkdimension/) function Construct a positive dimension without applying a command-specific maximum. [mkWindowIndex](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-mkwindowindex/) function Construct a nonnegative window-link index. [mkPaneIndex](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-mkpaneindex/) function Construct a nonnegative pane index. LibTmux.Value — Read numeric values 3 functions and constants [dimensionValue](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-dimensionvalue/) function Read a dimension as a mathematical integer, without narrowing conversion. [windowIndexValue](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-windowindexvalue/) function Read a window-link index as a mathematical integer. [paneIndexValue](https://libtmux.org/en/haskell/latest/reference/libtmux-value-v-paneindexvalue/) function Read a pane index as a mathematical integer. LibTmux.Version 1 type [LibTmux.Version](https://libtmux.org/en/haskell/latest/reference/libtmux-version/) module 5 members Parse stable tmux releases and check the supported release range. LibTmux.Version — Release identity and errors 2 functions and constants [TmuxVersion](https://libtmux.org/en/haskell/latest/reference/libtmux-version-t-tmuxversion/) data type A stable release, constructed by [`parseVersion`](https://libtmux.org/en/haskell/latest/reference/libtmux-version-v-parseversion/ "function") and rendered by [`renderVersion`](https://libtmux.org/en/haskell/latest/reference/libtmux-version-v-renderversion/ "function"). Ordering compares numeric components before the patch letter. [VersionError](https://libtmux.org/en/haskell/latest/reference/libtmux-version-t-versionerror/) data type 2 members Invalid release syntax or a release outside the supported range. LibTmux.Version — Parse and render 2 functions and constants [parseVersion](https://libtmux.org/en/haskell/latest/reference/libtmux-version-v-parseversion/) function Parse a stable release or the output of `tmux -V`, allowing one final LF. Development builds and trailing data are rejected rather than assigned capabilities from a guessed stable version. Diagnostics retain at most 64 chars. [renderVersion](https://libtmux.org/en/haskell/latest/reference/libtmux-version-v-renderversion/) function Render the canonical release without the executable name or newline. LibTmux.Version — Admit a release 1 function or constant [requireSupported](https://libtmux.org/en/haskell/latest/reference/libtmux-version-v-requiresupported/) function Admit every stable release from 3.3a through 3.8, including intermediate releases. Versions outside that range fail. Individual features need their own capability checks; passing this check does not qualify an entire release.