stuff

package.json

@@ -2,8 +2,12 @@
   "name": "println",
   "version": "1.0.0",
   "description": "",
-  "main": "index.js",
+  "main": "dist/index.js",
   "scripts": {
+    "watch": "pnpm '/watch:*/'",
+    "watch:build": "tsc --watch",
+    "watch:run": "node --watch .",
+    "dev": "node .",
     "build": "tsc"
   },
   "keywords": [],

src/index.ts

@@ -0,0 +1,334 @@
+// simple
+const TypeBoolean = Symbol("TypeBoolean");
+const TypeFontID = Symbol("TypeFontID");
+const TypeInteger = Symbol("TypeInteger");
+const TypeMark = Symbol("TypeMark");
+const TypeName = Symbol("TypeName");
+const TypeNull = Symbol("TypeNull");
+const TypeOperator = Symbol("TypeOperator");
+const TypeReal = Symbol("TypeReal");
+// composite
+const TypeArray = Symbol("TypeArray");
+const TypeDictionary = Symbol("TypeDictionary");
+const TypeFile = Symbol("TypeFile");
+const TypeGState = Symbol("TypeGState");
+const TypePackedArray = Symbol("TypePackedArray");
+const TypeSave = Symbol("TypeSave");
+const TypeString = Symbol("TypeString");
+
+type Name = number;
+
+type PsObjectBase =
+  | { type: typeof TypeBoolean; value: boolean }
+  | { type: typeof TypeFontID; value: number }
+  | { type: typeof TypeInteger; value: number }
+  | { type: typeof TypeMark }
+  | { type: typeof TypeName; name: Name }
+  | { type: typeof TypeNull }
+  | { type: typeof TypeOperator; implementation: (state: PSExecState) => void }
+  | { type: typeof TypeReal; value: number }
+  | { type: typeof TypeArray }
+  | {
+      type: typeof TypeDictionary;
+      // TODO: store in memory
+      values: Map<Name, PsObject>;
+    }
+  | { type: typeof TypeFile }
+  | { type: typeof TypeGState }
+  | { type: typeof TypePackedArray }
+  | { type: typeof TypeSave }
+  | { type: typeof TypeString };
+
+const AttrLiteral = Symbol("AttrLiteral");
+const AttrExecutable = Symbol("AttrExecute");
+
+const AccessUnlimited = Symbol("AccessUnlimited");
+const AccessReadOnly = Symbol("AccessReadOnly");
+const AccessExecuteOnly = Symbol("AccessExecuteOnly");
+const AccessNone = Symbol("AccessNone");
+
+type PsObject = PsObjectBase & {
+  litexec: typeof AttrLiteral | typeof AttrExecutable;
+  access:
+    | typeof AccessUnlimited
+    | typeof AccessReadOnly
+    | typeof AccessExecuteOnly
+    | typeof AccessNone;
+};
+
+type PsObjectBoolean = Extract<PsObject, { type: typeof TypeBoolean }>;
+type PsObjectFontID = Extract<PsObject, { type: typeof TypeFontID }>;
+type PsObjectInteger = Extract<PsObject, { type: typeof TypeInteger }>;
+type PsObjectMark = Extract<PsObject, { type: typeof TypeMark }>;
+type PsObjectName = Extract<PsObject, { type: typeof TypeName }>;
+type PsObjectNull = Extract<PsObject, { type: typeof TypeNull }>;
+type PsObjectOperator = Extract<PsObject, { type: typeof TypeOperator }>;
+type PsObjectReal = Extract<PsObject, { type: typeof TypeReal }>;
+type PsObjectArray = Extract<PsObject, { type: typeof TypeArray }>;
+type PsObjectDictionary = Extract<PsObject, { type: typeof TypeDictionary }>;
+type PsObjectFile = Extract<PsObject, { type: typeof TypeFile }>;
+type PsObjectGState = Extract<PsObject, { type: typeof TypeGState }>;
+type PsObjectPackedArray = Extract<PsObject, { type: typeof TypePackedArray }>;
+type PsObjectSave = Extract<PsObject, { type: typeof TypeSave }>;
+type PsObjectString = Extract<PsObject, { type: typeof TypeString }>;
+
+// stuff
+
+let nextNameIdx = 0;
+const nameIndicies: Map<string, Name> = new Map();
+const nameStrings: Map<Name, string> = new Map();
+const newName = (value: string): Name => {
+  let nameIdx = nameIndicies.get(value);
+  if (nameIdx !== undefined) {
+    return nameIdx;
+  }
+  nameIdx = nextNameIdx++;
+  nameIndicies.set(value, nameIdx);
+  nameStrings.set(nameIdx, value);
+  return nameIdx;
+};
+const nameString = (name: Name): string => {
+  const string = nameStrings.get(name);
+  if (string === undefined) {
+    throw new Error(`invalid name: ${name} has no associated string`);
+  }
+  return string;
+};
+
+// logic
+
+const file = function* (input: string) {
+  for (const char of input) {
+    yield char;
+  }
+};
+
+const scan = function* (
+  file: Generator<string>
+): Generator<PsObject, void, void> {
+  const splitter = function* (file: Generator<string>): Generator<string> {
+    const isWhitespace = (value: string) =>
+      value === " " || value === "\t" || value === "\r" || value === "\n";
+
+    let accumulator = "";
+    let next;
+    while (((next = file.next()), !next.done)) {
+      if (next.value === "(") {
+        throw new Error("todo (");
+      }
+
+      if (isWhitespace(next.value)) {
+        if (accumulator.length > 0) {
+          yield accumulator;
+        }
+        accumulator = "";
+        continue;
+      } else if (next.value === "%") {
+        while (((next = file.next()), !next.done && next.value !== "\n")) {}
+        continue;
+      } else if (
+        ["<", ">", "[", "]", "{", "}", "/", "%"].includes(next.value)
+      ) {
+        if (accumulator.length > 0) {
+          yield accumulator;
+        }
+        accumulator = "";
+      }
+
+      accumulator += next.value;
+    }
+
+    if (accumulator.length > 0) {
+      yield accumulator;
+    }
+  };
+
+  const tokens = splitter(file);
+
+  let next;
+  while (((next = tokens.next()), !next.done)) {
+    console.log("token", next.value);
+    switch (true) {
+      case /^\d+$/.test(next.value): {
+        const numericValue = parseInt(next.value, 10);
+        yield {
+          type: TypeInteger,
+          value: numericValue,
+          litexec: AttrLiteral,
+          access: AccessUnlimited,
+        };
+        break;
+      }
+      default: {
+        const isLiteral = next.value.startsWith("/");
+        const nameValue = newName(isLiteral ? next.value.slice(1) : next.value);
+        yield {
+          type: TypeName,
+          name: nameValue,
+          litexec: isLiteral ? AttrLiteral : AttrExecutable,
+          access: AccessUnlimited,
+        };
+      }
+    }
+  }
+};
+
+type Stack<T> = T[];
+
+type PSExecState = {
+  operandStack: Stack<PsObject>;
+  dictionaryStack: Stack<PsObjectDictionary>;
+  executionStack: Stack<PsObject>;
+};
+
+const initExecState = (): PSExecState => {
+  const systemdict: PsObjectDictionary = {
+    type: TypeDictionary,
+    values: new Map(),
+    litexec: AttrLiteral,
+    access: AccessReadOnly,
+  };
+
+  const defineOperator = (
+    name: string,
+    implementation: (state: PSExecState) => void
+  ) => {
+    systemdict.values.set(newName(name), {
+      type: TypeOperator,
+      litexec: AttrExecutable,
+      access: AccessReadOnly,
+      implementation,
+    });
+  };
+
+  // helpers
+  const popOperand = (state: PSExecState): PsObject => {
+    const value = state.operandStack.pop();
+    if (!value) {
+      throw new Error("error: stackunderflow");
+    }
+    return value;
+  };
+
+  defineOperator("add", (state) => {
+    const b = popOperand(state);
+    const a = popOperand(state);
+    if (a.type === TypeInteger && b.type === TypeInteger) {
+      state.operandStack.push({
+        type: TypeInteger,
+        litexec: AttrLiteral,
+        access: AccessUnlimited,
+        value: a.value + b.value,
+      });
+    }
+  });
+  defineOperator("def", (state) => {
+    const value = popOperand(state);
+    const key = popOperand(state);
+    const topDict = state.dictionaryStack.at(-1)!;
+    let name: Name;
+    if (key.type === TypeName) {
+      name = key.name;
+    } else {
+      throw new Error("todo: other def entries");
+    }
+    topDict.values.set(name, value);
+  });
+
+  const globaldict: PsObjectDictionary = {
+    type: TypeDictionary,
+    values: new Map(),
+    litexec: AttrLiteral,
+    access: AccessUnlimited,
+  };
+  const userdict: PsObjectDictionary = {
+    type: TypeDictionary,
+    values: new Map(),
+    litexec: AttrLiteral,
+    access: AccessUnlimited,
+  };
+
+  return {
+    operandStack: [],
+    dictionaryStack: [systemdict, globaldict, userdict],
+    executionStack: [],
+  };
+};
+
+const lookupDictionaryStack = (
+  stack: Stack<PsObjectDictionary>,
+  name: Name
+): PsObject | undefined => {
+  for (let i = stack.length - 1; i >= 0; i--) {
+    const dict = stack[i];
+    const value = dict?.values.get(name);
+    if (value) {
+      return value;
+    }
+  }
+  return undefined;
+};
+
+const executeObject = (state: PSExecState, object: PsObject) => {
+  console.log(object);
+
+  switch (object.type) {
+    case TypeInteger: {
+      state.operandStack.push(object);
+      break;
+    }
+    case TypeName: {
+      if (object.litexec === AttrLiteral) {
+        state.operandStack.push(object);
+      } else {
+        const value = lookupDictionaryStack(state.dictionaryStack, object.name);
+        if (!value) {
+          throw new Error(`error: 'undefined' '${nameString(object.name)}'`);
+        }
+        executeObject(state, value);
+      }
+      break;
+    }
+    case TypeOperator: {
+      if (object.litexec === AttrLiteral) {
+        state.operandStack.push(object);
+      } else {
+        object.implementation(state);
+      }
+      break;
+    }
+    case TypeNull: {
+      break;
+    }
+    default: {
+      throw new Error(
+        `cannot execute ${object.type.description}: ${JSON.stringify(object)}`
+      );
+    }
+  }
+};
+
+const execute = (state: PSExecState, input: Generator<PsObject>) => {
+  for (const object of input) {
+    executeObject(state, object);
+  }
+};
+
+// yeet
+
+const main = () => {
+  const program = `
+% meow
+/fourtytwo 42 def
+1 fourtytwo add
+`;
+
+  const f = file(program);
+  const scanner = scan(f);
+
+  const state = initExecState();
+  execute(state, scanner);
+  console.log(state.operandStack);
+};
+
+main();

tsconfig.json

@@ -25,12 +25,9 @@
     "exactOptionalPropertyTypes": true,
 
     // Style Options
-    // "noImplicitReturns": true,
+    "noImplicitReturns": true,
-    // "noImplicitOverride": true,
+    "noPropertyAccessFromIndexSignature": true,
-    // "noUnusedLocals": true,
+    "noFallthroughCasesInSwitch": true,
-    // "noUnusedParameters": true,
-    // "noFallthroughCasesInSwitch": true,
-    // "noPropertyAccessFromIndexSignature": true,
 
     // Recommended Options
     "strict": true,