1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
//! NAPI-RS tagged-enum From-impl code generation (binding ↔ core conversions).
use alef_core::ir::EnumDef;
use super::enums::{tagged_enum_binding_struct_fields, tagged_enum_mixed_named_fields};
use super::functions::{core_prim_str, needs_napi_cast};
/// Generate `From<JsTaggedEnum> for core::TaggedEnum` for a flattened struct representation.
pub(super) fn gen_tagged_enum_binding_to_core(
enum_def: &EnumDef,
core_import: &str,
prefix: &str,
struct_names: &ahash::AHashSet<String>,
) -> String {
use alef_core::ir::TypeRef;
use std::fmt::Write;
let core_path = alef_codegen::conversions::core_enum_path(enum_def, core_import);
let binding_name = format!("{prefix}{}", enum_def.name);
let tag_field = enum_def.serde_tag.as_deref().unwrap_or("type");
// Determine which Named fields use binding structs vs serde JSON String.
// A field uses a binding struct only if: (1) it has a binding struct in struct_names,
// (2) it's not sanitized, and (3) the field name maps to a single Named type across
// all variants (not shared with different types).
let fields_with_binding_struct = tagged_enum_binding_struct_fields(enum_def, struct_names);
// Fields with different Named types across variants are stored as String (JSON) in the
// binding struct and must be deserialized per-variant via serde_json.
let mixed_named_fields = tagged_enum_mixed_named_fields(enum_def);
let mut out = String::with_capacity(512);
writeln!(out, "impl From<{binding_name}> for {core_path} {{").ok();
writeln!(out, " fn from(val: {binding_name}) -> Self {{").ok();
writeln!(out, " match val.{tag_field}_tag.as_str() {{").ok();
for variant in &enum_def.variants {
let default_tag = variant.name.to_lowercase();
let tag_value = variant.serde_rename.as_deref().unwrap_or(&default_tag);
if variant.fields.is_empty() {
writeln!(out, " \"{tag_value}\" => Self::{},", variant.name).ok();
} else {
let is_tuple = alef_codegen::conversions::is_tuple_variant(&variant.fields);
let field_exprs: Vec<String> = variant
.fields
.iter()
.map(|f| {
let has_binding = fields_with_binding_struct.contains(f.name.as_str());
let is_mixed = mixed_named_fields.contains(&f.name);
if f.optional {
match &f.ty {
TypeRef::Path => {
format!("val.{}.map(std::path::PathBuf::from)", f.name)
}
TypeRef::Named(n) if is_mixed => {
// Mixed-type field: stored as String (JSON), deserialize per variant
let core_type = format!("{core_import}::{n}");
format!(
"val.{}.and_then(|s| serde_json::from_str::<{core_type}>(&s).ok())",
f.name
)
}
TypeRef::Named(_) if has_binding => {
format!("val.{}.map(|v| v.into())", f.name)
}
// Non-sanitized Named fields with a single consistent type are stored
// as Option<JsXxx> in the binding struct, so use .into() conversion.
TypeRef::Named(_) => {
format!("val.{}.map(|v| v.into())", f.name)
}
TypeRef::Primitive(p) if needs_napi_cast(p) => {
let core_ty = core_prim_str(p);
format!("val.{}.map(|v| v as {core_ty})", f.name)
}
_ => {
format!("val.{}", f.name)
}
}
} else if f.sanitized {
let expr = "Default::default()".to_string();
if f.is_boxed { format!("Box::new({expr})") } else { expr }
} else {
let expr = match &f.ty {
TypeRef::Named(n) if is_mixed => {
// Mixed-type field: stored as String (JSON), deserialize per variant
let core_type = format!("{core_import}::{n}");
format!(
"val.{}.and_then(|s| serde_json::from_str::<{core_type}>(&s).ok()).unwrap_or_default()",
f.name
)
}
TypeRef::Named(_) if has_binding => {
format!("val.{}.map(|v| v.into()).unwrap_or_default()", f.name)
}
// Non-sanitized Named fields with a single consistent type are stored
// as Option<JsXxx> in the binding struct, so use .into() conversion.
TypeRef::Named(_) => {
format!("val.{}.map(|v| v.into()).unwrap_or_default()", f.name)
}
TypeRef::Path => {
format!("val.{}.map(std::path::PathBuf::from).unwrap_or_default()", f.name)
}
TypeRef::Primitive(p) if needs_napi_cast(p) => {
let core_ty = core_prim_str(p);
format!("val.{}.map(|v| v as {core_ty}).unwrap_or_default()", f.name)
}
_ => {
format!("val.{}.unwrap_or_default()", f.name)
}
};
if f.is_boxed { format!("Box::new({expr})") } else { expr }
}
})
.collect();
if is_tuple {
writeln!(
out,
" \"{tag_value}\" => Self::{}({}),",
variant.name,
field_exprs.join(", ")
)
.ok();
} else {
let field_inits: Vec<String> = variant
.fields
.iter()
.zip(field_exprs.iter())
.map(|(f, expr)| format!("{}: {expr}", f.name))
.collect();
writeln!(
out,
" \"{tag_value}\" => Self::{} {{ {} }},",
variant.name,
field_inits.join(", ")
)
.ok();
}
}
}
// Default fallback to first variant
if let Some(first) = enum_def.variants.first() {
if first.fields.is_empty() {
writeln!(out, " _ => Self::{},", first.name).ok();
} else {
let is_tuple = alef_codegen::conversions::is_tuple_variant(&first.fields);
if is_tuple {
let defaults: Vec<&str> = first.fields.iter().map(|_| "Default::default()").collect();
writeln!(out, " _ => Self::{}({}),", first.name, defaults.join(", ")).ok();
} else {
let defaults: Vec<String> = first
.fields
.iter()
.map(|f| format!("{}: Default::default()", f.name))
.collect();
writeln!(
out,
" _ => Self::{} {{ {} }},",
first.name,
defaults.join(", ")
)
.ok();
}
}
}
writeln!(out, " }}").ok();
writeln!(out, " }}").ok();
write!(out, "}}").ok();
out
}
/// Generate `From<core::TaggedEnum> for JsTaggedEnum` for a flattened struct representation.
pub(super) fn gen_tagged_enum_core_to_binding(
enum_def: &EnumDef,
core_import: &str,
prefix: &str,
struct_names: &ahash::AHashSet<String>,
) -> String {
use std::fmt::Write;
let core_path = alef_codegen::conversions::core_enum_path(enum_def, core_import);
let binding_name = format!("{prefix}{}", enum_def.name);
let tag_field = enum_def.serde_tag.as_deref().unwrap_or("type");
let fields_with_binding_struct = tagged_enum_binding_struct_fields(enum_def, struct_names);
// Fields with different Named types across variants are stored as String (JSON) in the
// binding struct and must be serialized per-variant via serde_json.
let mixed_named_fields = tagged_enum_mixed_named_fields(enum_def);
// Collect all field names across all variants
let all_fields: Vec<String> = {
let mut fields = std::collections::BTreeSet::new();
for v in &enum_def.variants {
for f in &v.fields {
fields.insert(f.name.clone());
}
}
fields.into_iter().collect()
};
let mut out = String::with_capacity(512);
writeln!(out, "impl From<{core_path}> for {binding_name} {{").ok();
writeln!(out, " fn from(val: {core_path}) -> Self {{").ok();
writeln!(out, " match val {{").ok();
for variant in &enum_def.variants {
let default_tag = variant.name.to_lowercase();
let tag_value = variant.serde_rename.as_deref().unwrap_or(&default_tag);
let _variant_field_names: std::collections::BTreeSet<String> =
variant.fields.iter().map(|f| f.name.clone()).collect();
if variant.fields.is_empty() {
writeln!(
out,
" {core_path}::{} => Self {{ {tag_field}_tag: \"{tag_value}\".to_string(), {} }},",
variant.name,
all_fields
.iter()
.map(|f| format!("{f}: None"))
.collect::<Vec<_>>()
.join(", ")
)
.ok();
} else {
use alef_core::ir::TypeRef;
let is_tuple = alef_codegen::conversions::is_tuple_variant(&variant.fields);
let variant_field_map: std::collections::BTreeMap<&str, &alef_core::ir::FieldDef> =
variant.fields.iter().map(|f| (f.name.as_str(), f)).collect();
let destructured: Vec<String> = variant
.fields
.iter()
.map(|f| {
if f.sanitized {
if is_tuple {
format!("_{}", f.name)
} else {
format!("{}: _{}", f.name, f.name)
}
} else {
f.name.clone()
}
})
.collect();
let field_inits: Vec<String> = all_fields
.iter()
.map(|f| {
if let Some(field) = variant_field_map.get(f.as_str()) {
let has_binding = fields_with_binding_struct.contains(f.as_str());
let is_mixed = mixed_named_fields.contains(f.as_str());
if field.optional {
match &field.ty {
TypeRef::Path => format!("{f}: {f}.map(|p| p.to_string_lossy().to_string())"),
TypeRef::Named(_) if is_mixed => {
// Mixed-type field: serialize to JSON String for the binding struct
format!("{f}: {f}.and_then(|v| serde_json::to_string(&v).ok())")
}
TypeRef::Named(_) if has_binding => {
format!("{f}: {f}.map(|v| v.into())")
}
// Non-sanitized Named fields with a single consistent type are stored
// as Option<JsXxx> in the binding struct, so use .into() conversion.
TypeRef::Named(_) => {
format!("{f}: {f}.map(|v| v.into())")
}
_ => format!("{f}: {f}"),
}
} else if field.sanitized {
format!("{f}: None")
} else {
match &field.ty {
TypeRef::Named(_) if is_mixed => {
// Mixed-type field: serialize to JSON String for the binding struct
format!("{f}: serde_json::to_string(&{f}).ok()")
}
TypeRef::Named(_) if has_binding => format!("{f}: Some({f}.into())"),
// Non-sanitized Named fields with a single consistent type are stored
// as Option<JsXxx> in the binding struct, so use .into() conversion.
TypeRef::Named(_) => format!("{f}: Some({f}.into())"),
TypeRef::Path => format!("{f}: Some({f}.to_string_lossy().to_string())"),
TypeRef::Primitive(p) if needs_napi_cast(p) => {
match p {
alef_core::ir::PrimitiveType::F32 => format!("{f}: Some({f} as f64)"),
alef_core::ir::PrimitiveType::U64
| alef_core::ir::PrimitiveType::Usize
| alef_core::ir::PrimitiveType::Isize => format!("{f}: Some({f} as i64)"),
// U32 stays as-is in NAPI
_ => format!("{f}: Some({f})"),
}
}
_ => format!("{f}: Some({f})"),
}
}
} else {
format!("{f}: None")
}
})
.collect();
if is_tuple {
writeln!(
out,
" {core_path}::{}({}) => Self {{ {tag_field}_tag: \"{tag_value}\".to_string(), {} }},",
variant.name,
destructured.join(", "),
field_inits.join(", ")
)
.ok();
} else {
writeln!(
out,
" {core_path}::{} {{ {} }} => Self {{ {tag_field}_tag: \"{tag_value}\".to_string(), {} }},",
variant.name,
destructured.join(", "),
field_inits.join(", ")
)
.ok();
}
}
}
writeln!(out, " }}").ok();
writeln!(out, " }}").ok();
write!(out, "}}").ok();
out
}
/// Determine which Named fields in a tagged enum have **different** Named types across variants.
/// These fields cannot use a single `JsXxx` binding type, so they are stored as `String` (JSON)
/// and converted via `serde_json` per variant in the From impls.
#[cfg(test)]
mod tests {
/// gen_tagged_enum_binding_to_core is tested via integration tests in gen_bindings_test.rs.
/// This unit test verifies the function exists and is callable.
#[test]
fn tagged_enum_from_impls_exist() {
// Compilation check only — integration tests cover the generated output.
}
}