internal/rosa/azalea: re-construct expr text

This significantly helps with debugging: the %#v text is incredibly
unhelpful to read, and just ends up filling the terminal with useless
information.

Signed-off-by: Ophestra <cat@gensokyo.uk>

1 files changed, 30 insertions, 3 deletions

diff --git a/internal/rosa/azalea/evaluate.go b/internal/rosa/azalea/evaluate.go
index 1fb730f3..3b55f863 100644
--- a/internal/rosa/azalea/evaluate.go
+++ b/internal/rosa/azalea/evaluate.go
@@ -6,6 +6,7 @@ import (
 	"maps"
 	"reflect"
 	"slices"
+	"strconv"
 	"strings"
 	"unique"
 )
@@ -34,9 +35,6 @@ type (
 		V map[unique.Handle[Ident]]any
 	}
 
-	// Nil represents an untyped nil.
-	Nil struct{}
-
 	// AString represents an argument string that may be nil.
 	AString struct {
 		V   string
@@ -184,6 +182,35 @@ func store[T Value](rp any, r T) {
 	}
 }
 
+// ExprText is like the %#v printf verb, but for azalea expressions.
+func ExprText(expr any) string {
+	switch v := expr.(type) {
+	case fmt.Stringer:
+		return v.String()
+
+	case bool:
+		return strconv.FormatBool(v)
+
+	case []KV:
+		if len(v) == 0 {
+			return "{}"
+		}
+		s := make([]string, len(v))
+		for i, kv := range v {
+			s[i] = kv.String()
+		}
+		return "{\n\t" + strings.Join(s, "\n\t") + "\n}"
+
+	default:
+		return fmt.Sprint(expr)
+	}
+}
+
+// exprTextIndent is like [ExprText], but advances indentation by one level.
+func exprTextIndent(expr any) string {
+	return strings.ReplaceAll(ExprText(expr), "\n", "\n\t")
+}
+
 // EvaluationError is an error and the expression it occurred in.
 type EvaluationError struct {
 	Expr any