premise_macros

The reason macros. In Premise a value that somebody chose carries the reason they chose it, as code rather than as a comment. These are the macros that attach one.

use premise_macros::{because, source};

pub struct WearTest;
source!(WearTest, "the hinge fatigue test run on the entry door before fit-out");

pub const OPEN_LIMIT: u32 = 3;
because!(OPEN_LIMIT, WearTest, "three openings is where the test showed hinge fatigue");

macro	what it states
`because!(ITEM, [SOURCE,] "...")`	why this item is what it is, optionally citing a source
`source!(NAME, "...")`	a thing a reason may cite: a test, a measurement, a person's decision
`provisional!(ITEM, [SOURCE,] "...")`	nobody has decided yet, and this says what would settle it
`decided!(TYPE, TRAIT, "...")`	why a trait impl's associated values are what they are
`supersedes!(NEW, OLD, "...")`	this value replaced that one, and why
`rejected!(ITEM, "...")`	a value that was considered and turned down
`#[derive(Record)]`	reads a struct as named fields, for storage and transport

Each expands to an item a compiler checks. Nothing here formats or prints: the macros exist so that a reason has an identity, so a second reason for the same item is a duplicate the build can refuse and a missing one is an absence the build can see.

On their own these macros only record. What enforces them is the checker in the Premise repository, which refuses an item with no reason, a reason written twice, and a reason that only restates the name of the thing it explains.

This crate depends on nothing. It is a proc-macro crate and can be dropped into any Rust workspace whether or not the rest of Premise is there.

The manual is the repository README. It covers the four laws, every check, and a worked example end to end.

MIT licensed.

premise_macros 0.1.2

premise_macros

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