generic-cfg-builder: Move the statement handlers into this file

They very well belong there, and it makes reading the code easier.

Author: tmr232

src/control-flow/cfg-c.ts

@@ -5,8 +5,11 @@ import {
   type CFGBuilder,
 } from "./cfg-defs";
 import { Match } from "./block-matcher.ts";
-import type { Context, StatementHandlers } from "./statement-handlers.ts";
-import { GenericCFGBuilder } from "./generic-cfg-builder.ts";
+import {
+  GenericCFGBuilder,
+  type Context,
+  type StatementHandlers,
+} from "./generic-cfg-builder.ts";
 import { pairwise, zip } from "./zip.ts";
 import { buildSwitch, collectCases } from "./switch-utils.ts";
 

src/control-flow/cfg-go.ts

@@ -4,8 +4,11 @@ import {
   type BuilderOptions,
   type CFGBuilder,
 } from "./cfg-defs";
-import type { Context, StatementHandlers } from "./statement-handlers";
-import { GenericCFGBuilder } from "./generic-cfg-builder";
+import {
+  GenericCFGBuilder,
+  type Context,
+  type StatementHandlers,
+} from "./generic-cfg-builder";
 import { buildSwitch, collectCases, type SwitchOptions } from "./switch-utils";
 
 function getChildFieldText(node: Parser.SyntaxNode, fieldName: string): string {

src/control-flow/cfg-python.ts

@@ -4,8 +4,11 @@ import {
   type BuilderOptions,
   type CFGBuilder,
 } from "./cfg-defs";
-import type { Context, StatementHandlers } from "./statement-handlers.ts";
-import { GenericCFGBuilder } from "./generic-cfg-builder.ts";
+import {
+  GenericCFGBuilder,
+  type Context,
+  type StatementHandlers,
+} from "./generic-cfg-builder.ts";
 import { matchExistsIn } from "./block-matcher.ts";
 import { maybe, zip } from "./zip.ts";
 

src/control-flow/generic-cfg-builder.ts

@@ -6,11 +6,33 @@ import {
   type BuilderOptions,
   type CFG,
 } from "./cfg-defs";
-import type { StatementHandlers } from "./statement-handlers";
 import { BlockMatcher } from "./block-matcher";
 import { NodeMapper } from "./node-mapper";
 import { pairwise } from "./zip";
 
+interface Dispatch {
+  single(syntax: Parser.SyntaxNode | null): BasicBlock;
+  many(statements: Parser.SyntaxNode[]): BasicBlock;
+}
+interface Link {
+  syntaxToNode: InstanceType<typeof NodeMapper>["linkSytaxToNode"];
+  offsetToSyntax: InstanceType<typeof NodeMapper>["linkOffsetToSyntax"];
+}
+export interface Context {
+  builder: Builder;
+  options: BuilderOptions;
+  matcher: BlockMatcher;
+  dispatch: Dispatch;
+  state: BlockHandler;
+  link: Link;
+}
+
+type StatementHandler = (syntax: Parser.SyntaxNode, ctx: Context) => BasicBlock;
+export type StatementHandlers = {
+  named: { [key: string]: StatementHandler };
+  default: StatementHandler;
+};
+
 export class GenericCFGBuilder {
   private builder: Builder = new Builder();
   private readonly options: BuilderOptions;

src/control-flow/statement-handlers.ts

@@ -1,7 +1,7 @@
 import type Parser from "web-tree-sitter";
 import type { Case, EdgeType } from "./cfg-defs";
-import type { Context } from "./statement-handlers";
 import { pairwise } from "./zip";
+import type { Context } from "./generic-cfg-builder";
 export interface SwitchOptions {
   /// A Go `select` blocks until one of the branches matches.
   /// This means that we never add an alternative edge from the