Module mask 

Input-mask grammar (Qt-compatible subset).

Adopts the well-known QLineEdit::setInputMask grammar so masks that work in any Qt-based desktop app port over verbatim. Used by TextInputField to constrain typed input, render the empty-state template (__/__/____ for 99/99/9999), and auto-insert literal separators between editable positions.

Grammar

Char	Meaning
9	Required digit
0	Optional digit
A	Required ASCII letter
a	Optional ASCII letter
N	Required alphanumeric
n	Optional alphanumeric
X	Any required character
x	Any optional character
H	Required hex digit
h	Optional hex digit
>	Uppercase the following editable chars (toggle)
<	Lowercase the following editable chars (toggle)
!	Cancel the case lock from > / <
\X	Literal X (escape)

Anything else is a fixed separator: 99/99/9999, (999) 999-9999, >AA for force-uppercase 2-letter codes.

Storage model

The bound Signal<String> observes the formatted text including literal separators (matches Qt’s QLineEdit semantics): typing 12302026 into 99/99/9999 produces "12/30/2026", not "12302026". Apps that need raw digits strip separators trivially with .replace('/', "").

Structs

FormattedMask

Result of InputMask::format: the fully-templated string plus metadata about how much of the user’s input was consumed.

InputMask

Parsed mask: a sequence of positions, ready for rendering and per-character routing.

Enums

CaseLock

Per-position case lock applied during typing.

MaskClass

Character classes that an editable position accepts.

MaskError

Mask-parse errors. Currently only the trailing-backslash case; any other character becomes a fixed literal (Qt’s permissive behaviour) so most accidental “weird” masks just produce odd templates rather than parse failures.

MaskPosition

One position in the parsed mask. Either the user provides a character there (Editable) or it’s a fixed literal that the field paints automatically and the caret skips over.