ColorMode

`ColorMode`

Canonical source: protos/lib/text/ColorMode.protos at locked revision e99b712ecf658a527b1fe82c8beba2c1286d8dc9.

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//! Reusable color-mode policy. The three modes are `AUTO`, `ALWAYS`, and
//! `NEVER`. Each mode is its canonical String value: `ColorMode.AUTO` is
//! exactly `"AUTO"`, so a mode is immutable, compares with `===` and `==`, and
//! keeps its identity across Actor, Task, and Process boundaries without any
//! shared registry. No other spelling, alias, or letter case is a mode.
//!
//! Resolution is pure policy: it consults no environment, Process, standard
//! stream, terminal, or global configuration. Whether `AUTO` enables styling
//! is decided entirely by the caller, which supplies that Boolean to `resolve`
//! and passes the resolved Boolean to a renderer such as `std:text/ANSI`.

/// Styling follows the caller-supplied automatic decision.
AUTO: "AUTO"

/// Styling is always enabled.
ALWAYS: "ALWAYS"

/// Styling is never enabled.
NEVER: "NEVER"

/// Answers `true` exactly when `value` is one of the canonical modes and
/// `false` for any other value; it never signals an Error. Values are
/// recognized by String identity only, so no behavior of `value` is invoked.
recognizes: (value) => {
    (value === "AUTO") || (value === "ALWAYS") || (value === "NEVER")
}

/// Answers whether styling is enabled under `mode`: `AUTO` answers
/// `autoEnabled`, `ALWAYS` answers `true`, and `NEVER` answers `false`.
/// Both arguments are always validated, whatever the mode: `mode` must be a
/// canonical mode and `autoEnabled` must be exactly `true` or `false`; any
/// other argument signals an Error, and no argument is converted. No
/// environment or terminal is consulted to decide `AUTO`.
resolve: (mode, autoEnabled) => {
    validMode: (mode === "AUTO") || (mode === "ALWAYS") || (mode === "NEVER")
    validAuto: (autoEnabled === true) || (autoEnabled === false)
    (validMode && validAuto).ifFalse(() => {
        Error().signal()
    })
    result: autoEnabled
    (mode === "ALWAYS").ifTrue(() => {
        result = true
    })
    (mode === "NEVER").ifTrue(() => {
        result = false
    })
    result
}

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