lint some

lib/compress/reduce-vars.js

@@ -75,7 +75,6 @@ import {
     AST_Sequence,
     AST_SimpleStatement,
     AST_Symbol,
-    AST_SymbolBlockDeclaration,
     AST_SymbolCatch,
     AST_SymbolConst,
     AST_SymbolDefun,

lib/flow/conditionals.js

@@ -27,7 +27,7 @@ export function conditional(root_node, world = new World(), condition, body, alt
         const [body_exit, body_type] = catch_exit(body, then_world);
         const [alt_exit, alt_type] = alternative
             ? catch_exit(alternative, else_world)
-            : [null, UnknownType];
+            : [null, new LiteralType(undefined)];
 
         // Both exit
         if (body_exit && alt_exit) throw body_exit.OR(alt_exit);

lib/flow/dce.js

@@ -1,19 +1,19 @@
-import { TreeTransformer, AST_If, AST_Definitions, AST_VarDef, AST_Number, AST_Conditional, AST_EmptyStatement, AST_SymbolRef } from "../ast.js";
+import { TreeTransformer, AST_If, AST_Definitions, AST_Number, AST_Conditional } from "../ast.js";
 import { MAP, make_node } from "../utils/index.js";
 import { KNOWN_ELSE, KNOWN_THEN } from "./conditionals.js";
 import { World } from "./tools.js";
 
 // TODO move to utils?
-import { make_sequence, make_statements, to_statement } from "../compress/common.js";
+import { make_sequence, make_statements } from "../compress/common.js";
 
 export function flow_drop_dead_code(world = new World(), toplevel) {
     let tt = new TreeTransformer((node, descend, in_list) => {
         if (node instanceof AST_Conditional) {
             if (KNOWN_ELSE.has(node)) {
-                return node.alternative.transform(tt);
+                return keep_expression(tt, node, node.alternative);
             }
             if (KNOWN_THEN.has(node)) {
-                return node.consequent.transform(tt);
+                return keep_expression(tt, node, node.consequent);
             }
             return;
         }
@@ -62,7 +62,7 @@ function keep_expression(tt, orig, node) {
     if (!node) node = [];
     if (!Array.isArray(node)) node = [node];
     node = node.reduce((accum, node) => {
-        node = node && node.drop_side_effect_free(tt);
+        node = node && node.transform(tt);
         if (node) accum.push(node);
         return accum;
     }, []);

lib/flow/expressions.js

@@ -16,7 +16,7 @@ import { LiteralType } from "./types.js";
  */
 
 // CONSTANTS
-AST_Number.prototype._flow = function (world = new World()) {
+AST_Number.prototype._flow = function (_world = new World()) {
     return new LiteralType(this.value);
 };
 

lib/flow/flow.js

@@ -1,12 +1,12 @@
 // import { }
 
-import { AST_Defun, AST_Lambda, AST_Node, AST_Toplevel, AST_Var, walk, walk_parent } from "../ast.js";
+import { AST_Node, AST_Toplevel } from "../ast.js";
 
 import "./expressions.js";
 import "./lambda.js";
 import "./statements.js";
 
-import { Exit, analyze_func_or_toplevel_body, NOPE, sequential, World } from "./tools.js";
+import { Exit, analyze_func_or_toplevel_body, NOPE, World } from "./tools.js";
 
 /**
  * @module lib/flow/flow.js
@@ -39,7 +39,7 @@ AST_Toplevel.prototype.flow_analysis = function (world = new World()) {
     }
 };
 
-AST_Node.prototype._flow = function (world = new World()) {
+AST_Node.prototype._flow = function (_world = new World()) {
     throw NOPE;
 };
 

lib/flow/lambda.js

@@ -1,9 +1,9 @@
 import {AST_Call, AST_Defun, AST_Return} from "../ast.js";
-import {NOPE, World, sequential, Return, analyze_func_or_toplevel_body} from "./tools.js";
+import {NOPE, World, Return, analyze_func_or_toplevel_body} from "./tools.js";
 import {LiteralType, FunctionType } from "./types.js";
 
 // Defining the defun is done during hoisting (`hoist_defun_decls`)
-AST_Defun.prototype._flow = function (world = new World()) {
+AST_Defun.prototype._flow = function (_world = new World()) {
     return new LiteralType(undefined);
 };
 

lib/flow/statements.js

@@ -1,4 +1,4 @@
-import { AST_BlockStatement, AST_Definitions, AST_EmptyStatement, AST_If, AST_SimpleStatement, AST_Var } from "../ast.js";
+import { AST_BlockStatement, AST_Definitions, AST_EmptyStatement, AST_If, AST_SimpleStatement } from "../ast.js";
 import { World, sequential } from "./tools.js";
 import { conditional } from "./conditionals.js";
 import { LiteralType } from "./types.js";
@@ -13,7 +13,7 @@ AST_BlockStatement.prototype._flow = function (world = new World()) {
     return sequential(this.body, world.block_scope_world(this));
 };
 
-AST_EmptyStatement.prototype._flow = function (world = new World()) {
+AST_EmptyStatement.prototype._flow = function (_world = new World()) {
     return new LiteralType(undefined);
 };
 

lib/flow/tools.js

@@ -1,4 +1,4 @@
-import { AST_Const, AST_Definitions, AST_Defun, AST_Lambda, AST_Let, AST_Symbol, AST_Scope, AST_Var, AST_VarDef, walk_parent } from "../ast.js";
+import { AST_Const, AST_Definitions, AST_Defun, AST_Lambda, AST_Let, AST_Symbol, AST_Var, walk_parent } from "../ast.js";
 import { FunctionType, LiteralType } from "./types.js";
 import { map_map_set } from "../utils/index.js";
 
@@ -12,7 +12,7 @@ export function sequential(nodes, world) {
 }
 
 /** pre-walk to hoist declarations such as var and defun */
-export function analyze_func_or_toplevel_body(node_with_body, world = new World(), { allow_return } = {}) {
+export function analyze_func_or_toplevel_body(node_with_body, world = new World()) {
     const is_function = node_with_body instanceof AST_Lambda;
 
     const block_scopes = new Map();
@@ -111,7 +111,7 @@ export function catch_exit(node, world) {
     }
 }
 
-const binding_func_mask  = 0b10000000;
+const _binding_func_mask  = 0b10000000;
 const binding_block_mask = 0b01000000;
 const binding_const_mask = 0b00100000;
 
@@ -392,3 +392,4 @@ export class Return extends Exit {
 }
 
 export const NOPE = Symbol("NOPE (flow analysis impossible)");
+

lib/flow/types.js

@@ -14,13 +14,13 @@ export class Type {
     }
 
     OR(other) {
-        if (other === UnknownType) return other;
+        if (other === UnknownType || this.equals(other)) return other;
 
         const all_types = new Set([...this.types, ...other.types]);
         return new GenericType([...all_types]);
     }
 
-    equals(other) {
+    equals(_other) {
         throw new Error("not implemented (Type.equals)");
     }
 
@@ -34,12 +34,6 @@ export class GenericType extends Type {
         super(types);
     }
 
-    OR(other) {
-        if (other === UnknownType || this.equals(other)) return other;
-
-        return super.OR(other);
-    }
-
     equals(other) {
         return other === this
             || other instanceof GenericType
@@ -58,12 +52,6 @@ export class LiteralType extends Type {
         this.value = value;
     }
 
-    OR(other) {
-        if (other === UnknownType || this.equals(other)) return other;
-
-        return super.OR(other);
-    }
-
     equals(other) {
         return other === this
             || other instanceof LiteralType
@@ -83,6 +71,23 @@ export class FunctionType extends Type {
         this.parent_world = parent_world;
     }
 
+    equals(other) {
+        return other === this
+            || other instanceof FunctionType
+                && other.node === this.node
+                && other.parent_world === this.parent_world;
+    }
+
+    is_truthy() {
+        return true;
+    }
+}
+
+export class TrickyFunctionType extends Type {
+    constructor() {
+        super(["function"]);
+    }
+
     OR(other) {
         if (other === UnknownType || this.equals(other)) return other;
 
@@ -105,6 +110,7 @@ export const UnknownType = new (class extends Type {
     constructor() { super([]); }
 
     OR(_other) { return this; }
+    equals(other) { return this === other; }
     is_truthy() { return undefined; }
 })();
 

package.json

@@ -130,7 +130,8 @@
       "no-unused-vars": [
         "error",
         {
-          "varsIgnorePattern": "^_"
+          "varsIgnorePattern": "^_",
+          "argsIgnorePattern": "^_"
         }
       ],
       "no-tabs": "error",