fix function names

src/eval.js

@@ -68,7 +68,7 @@ const make_function = (...args) => {
   }
 }
 
-const codegen_function_expr = (node, cxt, name) => {
+const codegen_function_expr = (node, cxt) => {
   const do_codegen = n => codegen(n, cxt)
 
   const args = node.function_args.children.map(do_codegen).join(',')
@@ -90,7 +90,7 @@ const codegen_function_expr = (node, cxt, name) => {
   // on first call (see `trace`)
   const get_closure = `() => ({${[...node.closed].join(',')}})`
 
-  return `trace(${call}, "${name}", ${argscount}, ${location}, ${get_closure})`
+  return `trace(${call}, "${node.name}", ${argscount}, ${location}, ${get_closure})`
 }
 
 // TODO if statically can prove that function is hosted, then do not codegen
@@ -169,19 +169,7 @@ const codegen = (node, cxt, parent) => {
   } else if(node.type == 'function_call'){
     return codegen_function_call(node, cxt)
   } else if(node.type == 'function_expr'){
-    let name
-    // TODO here we deduce fn name from left-side of assignment
-    // TODO name inference is much more sophisticated, for example
-    // `{foo: () => {...}}` infers name `foo`
-    if(parent?.type == 'const') {
-      name = parent.name
-    } else if(parent?.type == 'key_value_pair') {
-      // unwrap quotes with JSON.parse
-      name = JSON.parse(parent.key.value)
-    } else {
-      name = 'anonymous'
-    }
-    return codegen_function_expr(node, cxt, name)
+    return codegen_function_expr(node, cxt)
   } else if(node.type == 'ternary'){
     return ''
     + '(' 
@@ -193,11 +181,20 @@ const codegen = (node, cxt, parent) => {
   } else if(node.type == 'const'){
     const res = 'const ' + do_codegen(node.name_node) + ' = ' + do_codegen(node.expr, node) + ';'
     if(node.name_node.type == 'identifier' && node.expr.type == 'function_call') {
-      // generate function name
-      // TODO test it
+      // deduce function name from variable it was assigned to if anonymous
+      // works for point-free programming, like
+      // const parse_statement = either(parse_import, parse_assignment, ...)
       return res + `
-        if(typeof(${node.name_node.value}) == 'function') {
-          Object.defineProperty(${node.name_node.value}, "name", {value: "${node.name_node.value}"});
+        if(
+          typeof(${node.name_node.value}) == 'function' 
+          && 
+          ${node.name_node.value}.name == 'anonymous'
+        ) {
+          Object.defineProperty(
+            ${node.name_node.value}, 
+            "name", 
+            {value: "${node.name_node.value}"}
+          );
         }
       `
     } else {
@@ -833,11 +830,10 @@ const do_eval_frame_expr = (node, scope, callsleft) => {
   } else if(node.type == 'function_expr'){
     // It will never be called, create empty function
     // TODO use new Function constructor with code?
-    // TODO generate function name
     const fn_placeholder = Object.defineProperty(
       () => {},
       'name',
-      {value: 'anonymous'}
+      {value: node.name}
     )
     return {
       ok: true,

src/parse_js.js

@@ -1452,6 +1452,44 @@ const update_children = node => {
   }
 }
 
+const do_deduce_fn_names = (node, parent) => {
+  let changed, node_result
+  if(node.children == null) {
+    node_result = node
+    changed = false
+  } else {
+    const children_results = node
+      .children
+      .map(c => do_deduce_fn_names(c, node))
+    changed = children_results.some(c => c[1])
+    if(changed) {
+      node_result = {...node, children: children_results.map(c => c[0])}
+    } else {
+      node_result = node
+    }
+  }
+
+  if(node_result.type == 'function_expr') {
+    let name
+    if(parent?.type == 'const') {
+      name = parent.name
+    } else if(parent?.type == 'key_value_pair') {
+      // unwrap quotes with JSON.parse
+      name = JSON.parse(parent.key.value)
+    } else {
+      name = 'anonymous'
+    }
+    changed = true
+    node_result = {...node_result, name}
+  }
+
+  return [node_result, changed]
+}
+
+const deduce_fn_names = node => {
+  return do_deduce_fn_names(node, null)[0]
+}
+
 export const parse = (str, is_module = false, module_name) => {
 
   // Add string to node for debugging
@@ -1499,7 +1537,12 @@ export const parse = (str, is_module = false, module_name) => {
         }],
       }
     } else {
-      const {node, undeclared} = find_definitions(update_children(result.value), null, null, module_name)
+      const {node, undeclared} = find_definitions(
+        update_children(result.value), 
+        null, 
+        null, 
+        module_name
+      )
       if(undeclared.length != 0){
         return {
           ok: false,
@@ -1516,7 +1559,7 @@ export const parse = (str, is_module = false, module_name) => {
         // property to some nodes, and children no more equal to other properties
         // of nodes by idenitity, which somehow breaks code (i dont remember how
         // exactly). Refactor it?
-        const fixed_node = update_children(populate_string(node))
+        const fixed_node = update_children(deduce_fn_names(populate_string(node)))
         const problems = analyze(fixed_node)
         if(problems.length != 0) {
           return {ok: false, problems}

test/test.js

@@ -461,24 +461,61 @@ export const tests = [
   }),
 
   test('function name from object literal', () => {
-    const i = test_initial_state(`
+    const code = `
       const fns = {x: () => 1}
       fns.x()
-    `)
+      fns.x.name
+    `
+    const i = test_initial_state(code)
     assert_equal(root_calltree_node(i).children[0].fn.name, 'x')
+    assert_code_evals_to(code, 'x')
   }),
 
-  test('function name', () => {
-    // TODO
-    /*
+  test('function name from const decl', () => {
+    const code = `
+      const x = () => 1
+      x()
+      x.name
+    `
+    const i = test_initial_state(code)
+    assert_equal(root_calltree_node(i).children[0].fn.name, 'x')
     assert_code_evals_to(
-      `
-      const x = () => null();
-      x.name;
-      `,
+      code,
       'x',
     )
-    */
+  }),
+
+  test('function name deduce', () => {
+    const code = `
+      const make_fn = () => () => 1
+      const x = make_fn()
+      x()
+      x.name
+    `
+    const i = test_initial_state(code)
+    assert_equal(root_calltree_node(i).children[1].fn.name, 'x')
+    assert_code_evals_to(
+      code,
+      'x',
+    )
+  }),
+
+  test('function name dont deduce if already has name', () => {
+    const code = `
+      const make_fn = () => {
+        const y = () => 1
+        return y
+      }
+      const x = make_fn()
+      x()
+      x.name
+    `
+    const i = test_initial_state(code)
+    assert_equal(root_calltree_node(i).children[1].fn.name, 'y')
+    assert_code_evals_to(
+      code,
+      'y',
+    )
   }),
 
   test('record call chain', () => {