$VersionNumber¶

Status: Stable

documented, exercised by the test suite and/or worked examples, with no known limitations recorded.

Description¶

$VersionNumber

gives the Mathilda version number as a real number.

Examples (4)¶

Every input below was run against the current Mathilda build and its output recorded.

Basic examples (2)¶

In[1]:= $VersionNumber
Out[1]= 0.46

In[2]:= $Version
Out[2]= "Mathilda 0.460 (GCC 16.1.0, GMP 6.3.0, MPFR 4.2.2, FLINT 3.6.0, ECM 7.0.7, Raylib 5.5, Accelerate, Readline)"

Applications (2)¶

Its head is Real

In[3]:= Head[$VersionNumber]
Out[3]= Real

A positive release number

In[4]:= $VersionNumber > 0
Out[4]= True

Implementation notes¶

What it is / where defined. $VersionNumber is a read-only system constant, bound as an OwnValue in system_constants_init (src/core.c) as register_system_constant("$VersionNumber", expr_new_real(MATHILDA_VERSION_NUMBER)) and then marked ATTR_PROTECTED. Its value is an EXPR_REAL.

Its value. MATHILDA_VERSION_NUMBER (src/version.h) is the single source of truth for the release — a C double such as 0.266 — with MATHILDA_VERSION_STRING its hand-synced textual twin feeding $Version. Every substantive commit bumps the number (conventionally by +0.001) and tags the commit v<MATHILDA_VERSION_STRING>.

Evaluation behaviour. Evaluates to the Real in one step and is Protected, so it cannot be reassigned. The printed form drops trailing zeros (so 0.160 prints as 0.16), and the value changes every release — a stable check therefore queries it structurally (Head[$VersionNumber] -> Real) rather than against a literal.

Attributes: Protected.

References¶

See also: $Version, Real

Source: src/core.c
Specification: docs/spec/builtins/expression-information.md

Notes & additional examples¶

Notes¶

$VersionNumber is a read-only Protected OwnValue giving the Mathilda release as a Real, such as 0.266. It comes straight from MATHILDA_VERSION_NUMBER in src/version.h, the single source of truth for the release; the descriptive form is $Version.

The numeric value changes every release (and the printer drops trailing zeros, so 0.160 would print as 0.16), so the examples test it structurally rather than against a literal.