json2go/transpiler.go (view raw)
| 1 | package json2go |
| 2 | |
| 3 | import ( |
| 4 | "strings" |
| 5 | "unicode" |
| 6 | ) |
| 7 | |
| 8 | // Transpiler transpiles AST [Value] to Go type definitions. |
| 9 | type Transpiler struct{} |
| 10 | |
| 11 | func NewTranspiler() *Transpiler { return &Transpiler{} } |
| 12 | |
| 13 | // Transpile converts a [Value] AST to Go type definitions. |
| 14 | func (t *Transpiler) Transpile(structName string, v Value, includeTags bool) (string, error) { |
| 15 | var buf strings.Builder |
| 16 | buf.WriteString("type ") |
| 17 | buf.WriteString(structName) |
| 18 | |
| 19 | switch v.Kind { |
| 20 | case ArrayValue: |
| 21 | buf.WriteString(" [") |
| 22 | if len(v.Array) == 0 { |
| 23 | buf.WriteString("]any") |
| 24 | } else { |
| 25 | buf.WriteByte(']') |
| 26 | t.writeInlineType(&buf, structName+"Item", v.Array[0], includeTags, 0) |
| 27 | } |
| 28 | |
| 29 | case ObjectValue: |
| 30 | buf.WriteByte(' ') |
| 31 | t.writeInlineStruct(&buf, structName, v.Object, includeTags, 0) |
| 32 | |
| 33 | default: |
| 34 | buf.WriteByte(' ') |
| 35 | t.writeScalarType(&buf, v) |
| 36 | } |
| 37 | |
| 38 | return buf.String(), nil |
| 39 | } |
| 40 | |
| 41 | func (t *Transpiler) writeInlineType(buf *strings.Builder, name string, v Value, includeTags bool, depth int) { |
| 42 | switch v.Kind { |
| 43 | case ObjectValue: |
| 44 | t.writeInlineStruct(buf, name, v.Object, includeTags, depth) |
| 45 | |
| 46 | case ArrayValue: |
| 47 | buf.WriteByte('[') |
| 48 | if len(v.Array) == 0 { |
| 49 | buf.WriteString("]any") |
| 50 | } else { |
| 51 | buf.WriteByte(']') |
| 52 | t.writeInlineType(buf, name+"Item", v.Array[0], includeTags, depth) |
| 53 | } |
| 54 | |
| 55 | default: |
| 56 | t.writeScalarType(buf, v) |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | func (t *Transpiler) writeIndent(buf *strings.Builder, depth int) { |
| 61 | for i := 0; i < depth; i++ { |
| 62 | buf.WriteByte('\t') |
| 63 | } |
| 64 | } |
| 65 | |
| 66 | func (t *Transpiler) writeInlineStruct(buf *strings.Builder, name string, fields []Field, includeTags bool, depth int) { |
| 67 | buf.WriteString("struct {\n") |
| 68 | for _, f := range fields { |
| 69 | fieldName := t.sanitizeFieldName(f.K) |
| 70 | t.writeIndent(buf, depth+1) |
| 71 | buf.WriteString(fieldName) |
| 72 | buf.WriteByte(' ') |
| 73 | t.writeInlineType(buf, name+fieldName, f.V, includeTags, depth+1) |
| 74 | if includeTags { |
| 75 | buf.WriteString(" `json:\"") |
| 76 | buf.WriteString(f.K) |
| 77 | buf.WriteString("\"`") |
| 78 | } |
| 79 | buf.WriteByte('\n') |
| 80 | } |
| 81 | t.writeIndent(buf, depth) |
| 82 | buf.WriteByte('}') |
| 83 | } |
| 84 | |
| 85 | func (t *Transpiler) writeScalarType(buf *strings.Builder, v Value) { |
| 86 | switch v.Kind { |
| 87 | case StringValue: |
| 88 | buf.WriteString("string") |
| 89 | case NumberValue: |
| 90 | buf.WriteString("int") |
| 91 | case DecimalValue: |
| 92 | buf.WriteString("float64") |
| 93 | case BoolValue: |
| 94 | buf.WriteString("bool") |
| 95 | default: |
| 96 | buf.WriteString("any") |
| 97 | } |
| 98 | } |
| 99 | |
| 100 | func (t *Transpiler) sanitizeFieldName(jsonKey string) string { |
| 101 | if jsonKey == "" { |
| 102 | return "Field" |
| 103 | } |
| 104 | |
| 105 | var result strings.Builder |
| 106 | result.Grow(len(jsonKey)) |
| 107 | |
| 108 | capitalize := true |
| 109 | for _, r := range jsonKey { |
| 110 | if r == '_' { |
| 111 | capitalize = true |
| 112 | continue |
| 113 | } |
| 114 | if capitalize { |
| 115 | result.WriteRune(unicode.ToUpper(r)) |
| 116 | capitalize = false |
| 117 | } else { |
| 118 | result.WriteRune(r) |
| 119 | } |
| 120 | } |
| 121 | |
| 122 | name := result.String() |
| 123 | if name != "" && isValidIdentifier(name) { |
| 124 | return name |
| 125 | } |
| 126 | |
| 127 | return t.sanitizeInvalidIdentifier(jsonKey) |
| 128 | } |
| 129 | |
| 130 | func (t *Transpiler) sanitizeInvalidIdentifier(jsonKey string) string { |
| 131 | var result strings.Builder |
| 132 | for i, r := range jsonKey { |
| 133 | if unicode.IsLetter(r) || r == '_' || (i > 0 && unicode.IsDigit(r)) { |
| 134 | result.WriteRune(r) |
| 135 | } else if i > 0 && r == '-' { |
| 136 | result.WriteRune('_') |
| 137 | } |
| 138 | } |
| 139 | |
| 140 | name := result.String() |
| 141 | if name == "" || (!unicode.IsLetter(rune(name[0])) && name[0] != '_') { |
| 142 | var b strings.Builder |
| 143 | b.Grow(len(name) + 1) |
| 144 | b.WriteByte('F') |
| 145 | b.WriteString(name) |
| 146 | return b.String() |
| 147 | } |
| 148 | |
| 149 | return name |
| 150 | } |