elvish/pkg/eval/vals/repr.go
Qi Xiao 6992c0b693 Make pseudomaps print like [^tag &key=value].
Also make file:pipe output a struct map rather than a pseudomap.
2023-07-17 23:41:43 +01:00

102 lines
2.9 KiB
Go

package vals
import (
"fmt"
"math"
"math/big"
"sort"
"strconv"
"src.elv.sh/pkg/parse"
"src.elv.sh/pkg/persistent/hashmap"
)
// Reprer wraps the Repr method.
type Reprer interface {
// Repr returns a string that represents a Value. The string either be a
// literal of that Value that is preferably deep-equal to it (like `[a b c]`
// for a list), or a string enclosed in "<>" containing the kind and
// identity of the Value(like `<fn 0xdeadcafe>`).
//
// If indent is at least 0, it should be pretty-printed with the current
// indentation level of indent; the indent of the first line has already
// been written and shall not be written in Repr. The returned string
// should never contain a trailing newline.
Repr(indent int) string
}
// ReprPlain is like Repr, but without pretty-printing.
func ReprPlain(v any) string {
return Repr(v, math.MinInt)
}
// Repr returns the representation for a value, a string that is preferably
// (but not necessarily) an Elvish expression that evaluates to the argument.
// The representation is pretty-printed, using indent as the initial level of
// indentation. It is implemented for the builtin types nil, bool and string,
// the File, List and Map types, StructMap types, and types satisfying the
// Reprer interface. For other types, it uses fmt.Sprint with the format
// "<unknown %v>".
func Repr(v any, indent int) string {
switch v := v.(type) {
case nil:
return "$nil"
case bool:
if v {
return "$true"
}
return "$false"
case string:
return parse.Quote(v)
case int:
return "(num " + strconv.Itoa(v) + ")"
case *big.Int:
return "(num " + v.String() + ")"
case *big.Rat:
return "(num " + v.String() + ")"
case float64:
return "(num " + formatFloat64(v) + ")"
case File:
return fmt.Sprintf("<file{%s %d}>", parse.Quote(v.Name()), v.Fd())
case List:
b := NewListReprBuilder(indent)
for it := v.Iterator(); it.HasElem(); it.Next() {
b.WriteElem(Repr(it.Elem(), indent+1))
}
return b.String()
case Map:
return reprMap(v.Iterator(), v.Len(), indent)
case StructMap:
return reprMap(iterateStructMap(v), lenStructMap(v), indent)
case Reprer:
return v.Repr(indent)
case PseudoMap:
m := v.Fields()
s := reprMap(iterateStructMap(m), lenStructMap(m), indent)
// Add a tag immediately after [.
return "[^" + Kind(v) + " " + s[1:]
default:
return fmt.Sprintf("<unknown %v>", v)
}
}
func reprMap(it hashmap.Iterator, n, indent int) string {
builder := NewMapReprBuilder(indent)
// Collect all the key-value pairs.
pairs := make([][2]any, 0, n)
for ; it.HasElem(); it.Next() {
k, v := it.Elem()
pairs = append(pairs, [2]any{k, v})
}
// Sort the pairs. See the godoc of CmpTotal for the sorting algorithm.
sort.Slice(pairs, func(i, j int) bool {
return CmpTotal(pairs[i][0], pairs[j][0]) == CmpLess
})
// Print the pairs.
for _, pair := range pairs {
k, v := pair[0], pair[1]
builder.WritePair(Repr(k, indent+1), indent+2, Repr(v, indent+2))
}
return builder.String()
}