Documentation
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Overview ¶
Package loomcheck enforces "import the loom combinator instead of hand-rolling it" through a syntax-only AST check.
The failure mode it targets is subtle: an author loads the fp-go style skills, writes a small `func(x T) bool { return ... }` inline, and ships code that looks perfectly idiomatic while silently reinventing a combinator this module already exports. Nothing in the compiler, the formatter, or golangci-lint objects, so the duplication survives review.
The rule flags a function literal that
- takes one parameter and returns a single bool, and
- has a body of exactly one return statement whose expression matches a shape loom already covers.
Condition 2 keeps the signal high: by default only recognized shapes are reported, each with the exact loom replacement named in the message. Set Config.StrictAllPredicates to also flag single-return bool literals whose shape is not recognized, which surfaces candidates for new loom combinators.
Opt out per function with a doc comment carrying the directive and a non-empty reason:
// fp-go:allow-hand-rolled-predicate SDK fixes this callback shape
func adapter() { ... }
Usage mirrors pipelinecheck — drop a thin test into any package:
func TestNoHandRolledPredicates(t *testing.T) {
loomcheck.Require(t, loomcheck.Config{Roots: []string{".."}})
}
Index ¶
Constants ¶
const DefaultAllowDirective = "fp-go:allow-hand-rolled-predicate"
DefaultAllowDirective exempts a function from the hand-rolled predicate rule. It must be followed by a non-empty reason.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Config ¶
type Config struct {
// Roots are directories scanned recursively for non-test .go
// files. Defaults to []string{"."} when empty.
Roots []string
// AllowDirective exempts a function from the rule. Defaults to
// DefaultAllowDirective when empty.
AllowDirective string
// SkipDirs are directory base names skipped during the walk, in
// addition to .git, testdata, vendor and node_modules.
SkipDirs []string
// StrictAllPredicates also reports single-return bool literals
// whose shape has no known loom replacement. Off by default.
StrictAllPredicates bool
}
Config configures a Check run.
type Reporter ¶
type Reporter interface {
Helper()
Errorf(format string, args ...any)
Fatalf(format string, args ...any)
}
Reporter is the subset of *testing.T that Require needs.
Source Files