all: make use of stringer in more places

This replaces about 100 lines of manually maintained code
with about 190 lines of automatically generated code with stringer.
The strings are now the constant names themselves, or in the case
of `stringer -linecomment`, in inline comments following the names.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I90e0463fcf82ebe2d6cfd43f90aed4442f71eb16
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1199854
Unity-Result: CUE porcuepine <[email protected]>
Reviewed-by: Matthew Sackman <[email protected]>
TryBot-Result: CUEcueckoo <[email protected]>

Author: mvdan

cue/token/position.go

@@ -115,36 +115,32 @@ var NoPos = Pos{}
 // RelPos indicates the relative position of token to the previous token.
 type RelPos int
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type=RelPos -linecomment
+
 const (
 	// NoRelPos indicates no relative position is specified.
-	NoRelPos RelPos = iota
+	NoRelPos RelPos = iota // invalid
 
 	// Elided indicates that the token for which this position is defined is
 	// not rendered at all.
-	Elided
+	Elided // elided
 
 	// NoSpace indicates there is no whitespace before this token.
-	NoSpace
+	NoSpace // nospace
 
 	// Blank means there is horizontal space before this token.
-	Blank
+	Blank // blank
 
 	// Newline means there is a single newline before this token.
-	Newline
+	Newline // newline
 
 	// NewSection means there are two or more newlines before this token.
-	NewSection
+	NewSection // section
 
 	relMask  = 0xf
 	relShift = 4
 )
 
-var relNames = []string{
-	"invalid", "elided", "nospace", "blank", "newline", "section",
-}
-
-func (p RelPos) String() string { return relNames[p] }
-
 func (p RelPos) Pos() Pos {
 	return Pos{nil, int(p)}
 }

cue/token/relpos_string.go

@@ -499,6 +499,8 @@ func (s *StructInfo) useForAccept() bool {
 // vertexStatus indicates the evaluation progress of a Vertex.
 type vertexStatus int8
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type=vertexStatus
+
 const (
 	// unprocessed indicates a Vertex has not been processed before.
 	// Value must be nil.
@@ -529,25 +531,6 @@ const (
 	finalized
 )
 
-func (s vertexStatus) String() string {
-	switch s {
-	case unprocessed:
-		return "unprocessed"
-	case evaluating:
-		return "evaluating"
-	case partial:
-		return "partial"
-	case conjuncts:
-		return "conjuncts"
-	case evaluatingArcs:
-		return "evaluatingArcs"
-	case finalized:
-		return "finalized"
-	default:
-		return "unknown"
-	}
-}
-
 func (v *Vertex) Status() vertexStatus {
 	return v.status
 }

internal/core/adt/composite.go

@@ -152,6 +152,8 @@ func openDebugGraph(ctx *OpContext, v *Vertex, name string) {
 // dependencies are balanced.
 type depKind int
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type=depKind
+
 const (
 	// PARENT dependencies are used to track the completion of parent
 	// closedContexts within the closedness tree.
@@ -200,37 +202,6 @@ const (
 	TEST // Always refers to self.
 )
 
-func (k depKind) String() string {
-	switch k {
-	case PARENT:
-		return "PARENT"
-	case ARC:
-		return "ARC"
-	case NOTIFY:
-		return "NOTIFY"
-	case TASK:
-		return "TASK"
-	case DISJUNCT:
-		return "DISJUNCT"
-	case EVAL:
-		return "EVAL"
-	case COMP:
-		return "COMP"
-	case ROOT:
-		return "ROOT"
-
-	case INIT:
-		return "INIT"
-	case DEFER:
-		return "DEFER"
-	case SHARED:
-		return "SHARED"
-	case TEST:
-		return "TEST"
-	}
-	panic("unreachable")
-}
-
 // ccDep is used to record counters which is used for debugging only.
 // It is purpose is to be precise about matching inc/dec as well as to be able
 // to traverse dependency.

internal/core/adt/debug.go

@@ -42,45 +42,31 @@ import (
 // control flow. No other aspects of an error may influence control flow.
 type ErrorCode int8
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type=ErrorCode -linecomment
+
 const (
 	// An EvalError is a fatal evaluation error.
-	EvalError ErrorCode = iota
+	EvalError ErrorCode = iota // eval
 
 	// A UserError is a fatal error originating from the user.
-	UserError
+	UserError // user
 
 	// StructuralCycleError means a structural cycle was found. Structural
 	// cycles are permanent errors, but they are not passed up recursively,
 	// as a unification of a value with a structural cycle with one that
 	// doesn't may still give a useful result.
-	StructuralCycleError
+	StructuralCycleError // structural cycle
 
 	// IncompleteError means an evaluation could not complete because of
 	// insufficient information that may still be added later.
-	IncompleteError
+	IncompleteError // incomplete
 
 	// A CycleError indicates a reference error. It is considered to be
 	// an incomplete error, as reference errors may be broken by providing
 	// a concrete value.
-	CycleError
+	CycleError // cycle
 )
 
-func (c ErrorCode) String() string {
-	switch c {
-	case EvalError:
-		return "eval"
-	case UserError:
-		return "user"
-	case StructuralCycleError:
-		return "structural cycle"
-	case IncompleteError:
-		return "incomplete"
-	case CycleError:
-		return "cycle"
-	}
-	return "unknown"
-}
-
 // Bottom represents an error or bottom symbol.
 //
 // Although a Bottom node holds control data, it should not be created until the

internal/core/adt/depkind_string.go

@@ -176,6 +176,8 @@ func (s schedState) String() string {
 // runMode indicates how to proceed after a condition could not be met.
 type runMode uint8
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type=runMode
+
 const (
 	// ignore indicates that the new evaluator should not do any processing.
 	// This is mostly used in the transition from old to new evaluator and
@@ -196,20 +198,6 @@ const (
 	finalize
 )
 
-func (r runMode) String() string {
-	switch r {
-	case ignore:
-		return "ignore"
-	case attemptOnly:
-		return "attemptOnly"
-	case yield:
-		return "yield"
-	case finalize:
-		return "finalize"
-	}
-	return "unknown"
-}
-
 // condition is a bit mask of states that a task may depend on.
 //
 // There are generally two types of states: states that are met if all tasks

internal/core/adt/errorcode_string.go

@@ -13,26 +13,17 @@ type Logger interface {
 
 type EventKind int
 
+//go:generate go run golang.org/x/tools/cmd/stringer -type=EventKind -linecomment
+
 const (
-	NoEvent EventKind = iota
-	KindClientSendRequest
-	KindClientRecvResponse
+	NoEvent                EventKind = iota
+	KindClientSendRequest            // http client->
+	KindClientRecvResponse           // http client<-
 
 	// TODO KindServerRecvRequest
 	// TODO KindServerSendResponse
 )
 
-func (k EventKind) String() string {
-	switch k {
-	case KindClientSendRequest:
-		return "http client->"
-	case KindClientRecvResponse:
-		return "http client<-"
-	default:
-		return "unknown"
-	}
-}
-
 // Request represents an HTTP request.
 type Request struct {
 	ID            int64       `json:"id"`