Adding builtins as native-functions. desugaring symbols as native function application. except ~ which is the new pipe operator, > is now greater than

src/builtins.ts

@@ -0,0 +1,447 @@
+import type { Value, NativeFunction } from './types'
+
+function expectInt(v: Value, name: string): number {
+    if (v.kind !== 'int')
+        throw new Error(`${name} expects int, got ${v.kind}`);
+    return v.value;
+}
+
+// function expectFloat(v: Value, name: string): number {
+//     if (v.kind !== 'float')
+//         throw new Error(`${name} expects float, got ${v.kind}`);
+//     return v.value;
+// }
+
+function expectNumber(v: Value, name: string): number {
+    if (v.kind !== 'float' && v.kind !== 'int')
+        throw new Error(`${name} expects number, got ${v.kind}`);
+    return v.value;
+}
+
+// function expectString(v: Value, name: string): string {
+//     if (v.kind !== 'string')
+//         throw new Error(`${name} expects string, got ${v.kind}`);
+//     return v.value;
+// }
+
+// function expectList(v: Value, name: string): Value[] {
+//     if (v.kind !== 'list')
+//         throw new Error(`${name} expects list, got ${v.kind}`);
+//     return v.elements;
+// }
+
+export const builtins: { [name: string]: NativeFunction } = {
+    // Arithmetic
+    'add': {
+        kind: 'native',
+        name: 'add',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'add');
+            const y = expectNumber(b, 'add');
+            return { kind: 'int', value: x + y };
+        }
+    },
+
+    'sub': {
+        kind: 'native',
+        name: 'sub',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'sub');
+            const y = expectNumber(b, 'sub');
+            return { kind: 'int', value: x - y };
+        }
+    },
+
+    'mul': {
+        kind: 'native',
+        name: 'mul',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'mul');
+            const y = expectNumber(b, 'mul');
+            return { kind: 'int', value: x * y };
+        }
+    },
+
+    'div': {
+        kind: 'native',
+        name: 'div',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'div');
+            const y = expectNumber(b, 'div');
+            return { kind: 'int', value: Math.floor(x / y) };
+        }
+    },
+
+    'mod': {
+        kind: 'native',
+        name: 'mod',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectInt(a, 'mod');
+            const y = expectInt(b, 'mod');
+            return { kind: 'int', value: x % y };
+        }
+    },
+
+    'pow': {
+        kind: 'native',
+        name: 'pow',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'add');
+            const y = expectNumber(b, 'add');
+            return { kind: 'int', value: Math.pow(x, y) };
+        }
+    },
+
+    // Comparison
+    'eq': {
+        kind: 'native',
+        name: 'eq',
+        arity: 2,
+        fn: (a, b) => {
+            return {
+                kind: 'constructor',
+                name: JSON.stringify(a) === JSON.stringify(b) ? 'True' : 'False',
+                args: []
+            };
+        }
+    },
+
+    'neq': {
+        kind: 'native',
+        name: 'eq',
+        arity: 2,
+        fn: (a, b) => {
+            return {
+                kind: 'constructor',
+                name: JSON.stringify(a) !== JSON.stringify(b) ? 'True' : 'False',
+                args: []
+            };
+        }
+    },
+
+    'lt': {
+        kind: 'native',
+        name: 'lt',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'lt');
+            const y = expectNumber(b, 'lt');
+            return {
+                kind: 'constructor',
+                name: x < y ? 'True' : 'False',
+                args: []
+            };
+        }
+    },
+
+    'gt': {
+        kind: 'native',
+        name: 'gt',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'gt');
+            const y = expectNumber(b, 'gt');
+            return {
+                kind: 'constructor',
+                name: x > y ? 'True' : 'False',
+                args: []
+            };
+        }
+    },
+
+    'lte': {
+        kind: 'native',
+        name: 'lt',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'lte');
+            const y = expectNumber(b, 'lt');
+            return {
+                kind: 'constructor',
+                name: x <= y ? 'True' : 'False',
+                args: []
+            };
+        }
+    },
+
+    'gte': {
+        kind: 'native',
+        name: 'gte',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'gte');
+            const y = expectNumber(b, 'gte');
+            return {
+                kind: 'constructor',
+                name: x >= y ? 'True' : 'False',
+                args: []
+            };
+        }
+    },
+
+    // String & List
+    'cat': {
+        kind: 'native',
+        name: 'cat',
+        arity: 2,
+        fn: (a, b) => {
+            if (a.kind === 'string' && b.kind === 'string') {
+                return { kind: 'string', value: a.value + b.value };
+            }
+            if (a.kind === 'list' && b.kind === 'list') {
+                return { kind: 'list', elements: [...a.elements, ...b.elements] };
+            }
+            throw new Error('cat requires 2 lists or 2 strings');
+        }
+    },
+
+    'len': {
+        kind: 'native',
+        name: 'len',
+        arity: 1,
+        fn: (seq) => {
+            if (seq.kind === 'string') {
+                return { kind: 'int', value: seq.value.length };
+            }
+            if (seq.kind === 'list') {
+                return { kind: 'int', value: seq.elements.length };
+            }
+            throw new Error('cat requires a list or a string');
+        }
+    },
+
+    'at': {
+        kind: 'native',
+        name: 'at',
+        arity: 2,
+        fn: (seq, idx) => {
+            const i = expectInt(idx, 'at');
+
+            if (seq.kind === 'string') {
+                return { kind: 'string', value: seq.value[i] || '' };
+            }
+            if (seq.kind === 'list') {
+                return seq.elements[i];
+            }
+            throw new Error('at requires a list or a string');
+        }
+    },
+
+    'slice': {
+        kind: 'native',
+        name: 'slice',
+        arity: 3,
+        fn: (seq, start, end) => {
+            const s = expectInt(start, 'slice');
+            const e = expectInt(end, 'slice');
+
+            if (seq.kind === 'string') {
+                return { kind: 'string', value: seq.value.slice(s, e) };
+            }
+            if (seq.kind === 'list') {
+                return { kind: 'list', elements: seq.elements.slice(s, e) };
+            }
+            throw new Error('slice requires a list or a string');
+        }
+    },
+
+    'head': {
+        kind: 'native',
+        name: 'head',
+        arity: 1,
+        fn: (seq) => {
+            if (seq.kind === 'string') {
+                if (seq.value.length === 0) {
+                    return { kind: 'constructor', name: 'None', args: [] };
+                }
+                return { kind: 'constructor', name: 'Some', args: [{ kind: 'string', value: seq.value[0] }] };
+            }
+            if (seq.kind === 'list') {
+                if (seq.elements.length === 0) {
+                    return { kind: 'constructor', name: 'None', args: [] };
+                }
+                return { kind: 'constructor', name: 'Some', args: [seq.elements[0]] };
+            }
+            throw new Error('head requires a list or a string');
+        }
+    },
+
+    'tail': {
+        kind: 'native',
+        name: 'tail',
+        arity: 1,
+        fn: (seq) => {
+            if (seq.kind === 'string') {
+                if (seq.value.length === 0) {
+                    return { kind: 'constructor', name: 'None', args: [] };
+                }
+                return { kind: 'constructor', name: 'Some', args: [{ kind: 'string', value: seq.value.slice(1) }] };
+            }
+            if (seq.kind === 'list') {
+                if (seq.elements.length === 0) {
+                    return { kind: 'constructor', name: 'None', args: [] };
+                }
+                return { kind: 'constructor', name: 'Some', args: [{ kind: 'list', elements: seq.elements.slice(1) }] };
+            }
+            throw new Error('tail requires a list or a string');
+        }
+    },
+
+    // Types
+    'str': {
+        kind: 'native',
+        name: 'str',
+        arity: 1,
+        fn: (val) => {
+            if (val.kind === 'int' || val.kind === 'float')
+                return { kind: 'string', value: val.value.toString() }
+
+            if (val.kind === 'string')
+                return val;
+
+            throw new Error('str: cannot convert to string');
+        }
+    },
+
+    'int': {
+        kind: 'native',
+        name: 'int',
+        arity: 1,
+        fn: (val) => {
+            if (val.kind === 'int')
+                return val;
+
+            if (val.kind === 'float')
+                return { kind: 'int', value: Math.floor(val.value) };
+
+            if (val.kind === 'string') {
+                const parsed = parseInt(val.value, 10);
+
+                if (isNaN(parsed))
+                    throw new Error(`int: cannot parse "${val.value}"`);
+
+                return { kind: 'int', value: parsed }
+            }
+
+            throw new Error(`int: cannot convert to int`);
+        }
+    },
+
+    'float': {
+        kind: 'native',
+        name: 'float',
+        arity: 1,
+        fn: (val) => {
+            if (val.kind === 'float')
+                return val;
+
+            if (val.kind === 'int')
+                return { kind: 'float', value: val.value };
+
+            if (val.kind === 'string') {
+                const parsed = parseFloat(val.value, 10);
+
+                if (isNaN(parsed))
+                    throw new Error(`float: cannot parse "${val.value}"`);
+
+                return { kind: 'float', value: parsed }
+            }
+
+            throw new Error(`float: cannot convert to float`);
+        }
+    },
+
+    // Math
+    'sqrt': {
+        kind: 'native',
+        name: 'sqrt',
+        arity: 1,
+        fn: (val) => {
+            const x = expectNumber(val, 'sqrt');
+            return { kind: 'float', value: Math.sqrt(x) };
+        }
+    },
+
+    'abs': {
+        kind: 'native',
+        name: 'abs',
+        arity: 1,
+        fn: (val) => {
+            if (val.kind === 'int')
+                return { kind: 'int', value: Math.abs(val.value) };
+
+            if (val.kind === 'float')
+                return { kind: 'float', value: Math.abs(val.value) };
+
+            throw new Error('abs expects a number');
+        }
+    },
+
+    'floor': {
+        kind: 'native',
+        name: 'floor',
+        arity: 1,
+        fn: (val) => {
+            const x = expectNumber(val, 'floor');
+            return { kind: 'int', value: Math.floor(x) };
+        }
+    },
+
+    'ceil': {
+        kind: 'native',
+        name: 'ceil',
+        arity: 1,
+        fn: (val) => {
+            const x = expectNumber(val, 'ceil');
+            return { kind: 'int', value: Math.ceil(x) };
+        }
+    },
+
+    'round': {
+        kind: 'native',
+        name: 'round',
+        arity: 1,
+        fn: (val) => {
+            const x = expectNumber(val, 'round');
+            return { kind: 'int', value: Math.round(x) };
+        }
+    },
+
+    'min': {
+        kind: 'native',
+        name: 'min',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'min');
+            const y = expectNumber(b, 'min');
+            const result = Math.min(x, y);
+
+            if (a.kind === 'float' || b.kind === 'float')
+                return { kind: 'float', value: result };
+
+            return { kind: 'int', value: result };
+        }
+    },
+
+    'max': {
+        kind: 'native',
+        name: 'max',
+        arity: 2,
+        fn: (a, b) => {
+            const x = expectNumber(a, 'max');
+            const y = expectNumber(b, 'max');
+            const result = Math.max(x, y);
+
+            if (a.kind === 'float' || b.kind === 'float')
+                return { kind: 'float', value: result };
+
+            return { kind: 'int', value: result };
+        }
+    },
+}

src/counter.cg

@@ -6,6 +6,7 @@ view = count \
     Column {
         gap = 20,
         children = [
+            Text({ content = str(count), x = 0, y = 20 }),
             Clickable {
                 event = "increment",
                 child = Rect { w = 100, h = 40, color = "blue" }

src/interpreter.ts

@@ -87,23 +87,33 @@ export function evaluate(ast: AST, env: Env): Value {
             }
 
         case 'apply': {
-            // Operators
-            if (ast.func.kind === 'variable') {
-                const name = ast.func.name;
-                const builtIns = ['+', '-', '*', '/', '>', '&'];
-
-                if (builtIns.includes(name)) {
+            const func = evaluate(ast.func, env);
             const argValues = ast.args.map(arg => evaluate(arg, env));
 
-                    if (argValues.length !== 2) {
-                        throw new Error(`${name} expects 2 args`);
+            // Native functions
+            if (func.kind === 'native') {
+                // Exact args
+                if (argValues.length === func.arity) {
+                    return func.fn(...argValues);
                 }
 
-                    return evaluateBuiltIn(name, argValues[0], argValues[1]);
+                // Partial application
+                if (argValues.length < func.arity) {
+                    const capturedArgs = argValues;
+
+                    return {
+                        kind: 'native',
+                        name: func.name,
+                        arity: func.arity - argValues.length,
+                        fn: (...restArgs: Value[]) => {
+                            return func.fn(...capturedArgs, ...restArgs);
+
                         }
+                    };
                 }
 
-            const func = evaluate(ast.func, env);
+                throw new Error(`Function expects ${func.arity} args, but got ${argValues.length}`);
+            }
 
             // Constructor application
             if (func.kind === 'constructor') {
@@ -118,8 +128,6 @@ export function evaluate(ast: AST, env: Env): Value {
             if (func.kind !== 'closure')
                 throw new Error('Not a function');
 
-            const argValues = ast.args.map(arg => evaluate(arg, env));
-
             // Too few args (Currying)
             if (argValues.length < func.params.length) {
                 // Bind the params we have
@@ -173,72 +181,6 @@ export function evaluate(ast: AST, env: Env): Value {
     }
 }
 
-function evaluateBinaryOp(op: string, left: Value, right: Value): Value {
-    const leftKind = left.kind;
-    const rightKind = right.kind;
-
-    const bothNumbers = ((leftKind === 'int' || leftKind === 'float')) && ((rightKind === 'int' || rightKind === 'float'));
-    if (!bothNumbers)
-        throw new Error(`Not numbers: ${left}, ${right}`);
-
-    const leftValue = left.value;
-    const rightValue = right.value;
-
-    switch (op) {
-        case '+':
-            return { value: leftValue + rightValue, kind: 'int' };
-
-        case '-':
-            return { value: leftValue - rightValue, kind: 'int' };
-
-        case '*':
-            return { value: leftValue * rightValue, kind: 'int' }
-
-        case '/':
-            return { value: leftValue / rightValue, kind: 'int' }
-
-        default:
-                throw new Error(`Unknown operation: ${op}`);
-    }
-}
-
-function evaluateBuiltIn(op: string, left: Value, right: Value): Value {
-    if (op === '+' || op === '-' || op === '*' || op === '/') {
-        return evaluateBinaryOp(op, left, right);
-    }
-
-    if (op === '>') {
-        // x > f means f(x)
-        if (right.kind !== 'closure')
-            throw new Error('Right side of > must be a function');
-
-        if (right.params.length !== 1)
-            throw new Error('Pipe only works with 1-arg functions for now..');
-
-        const callEnv = new Map(right.env);
-        callEnv.set(right.params[0], left);
-        return evaluate(right.body, callEnv);
-    }
-
-    if (op === '&') {
-        if (left.kind == 'list' && right.kind === 'list') {
-            return {
-                kind: 'list',
-                elements: [...left.elements, ...right.elements]
-            };
-        }
-
-        if (left.kind == 'string' && right.kind === 'string') {
-            return {
-                kind: 'string',
-                value: left.value + right.value
-            };
-        }
-    }
-
-    throw new Error(`Unknown built-in: ${op}`);
-}
-
 type Bindings = { [key: string]: Value };
 
 function matchPattern(value: Value, pattern: Pattern): Bindings | null {

src/lexer.ts

@@ -14,13 +14,21 @@ export type Token =
     | { kind: 'open-bracket' }
     | { kind: 'close-bracket' }
 
-    // Symbols
+    // Comparison
     | { kind: 'equals' }
+    | { kind: 'equals-equals' }
+    | { kind: 'not-equals' }
+    | { kind: 'greater-than' }
+    | { kind: 'greater-equals' }
+    | { kind: 'less-than' }
+    | { kind: 'less-equals' }
+
+    // Symbols
     | { kind: 'colon' }
     | { kind: 'semicolon' }
     | { kind: 'backslash' }
     | { kind: 'pipe' }
-    | { kind: 'greater-than' }
+    | { kind: 'tilde' }
     | { kind: 'comma' }
     | { kind: 'ampersand' }
     | { kind: 'underscore' }
@@ -32,6 +40,8 @@ export type Token =
     | { kind: 'minus' }
     | { kind: 'star' }
     | { kind: 'slash' }
+    | { kind: 'percent' }
+    | { kind: 'caret' }
 
     | { kind: 'eof' }
 
@@ -137,25 +147,49 @@ export function tokenize(source: string): Token[] {
         }
 
         switch (char) {
-            // Brackets
-            case '(': tokens.push({ kind: 'open-paren' }); break;
-            case ')': tokens.push({ kind: 'close-paren' }); break;
-            case '{': tokens.push({ kind: 'open-brace' }); break;
-            case '}': tokens.push({ kind: 'close-brace' }); break;
-            case '[': tokens.push({ kind: 'open-bracket' }); break;
-            case ']': tokens.push({ kind: 'close-bracket' }); break;
-
-            // Symbols
-            case '=': tokens.push({ kind: 'equals' }); break;
+            case '>': {
+                if (source[i + 1] == '=') {
+                    tokens.push({ kind: 'greater-equals' });
+                    i++;
+                } else {
+                    tokens.push({ kind: 'greater-than' });
+                }
+                break;
+            }
+            case '<': {
+                if (source[i + 1] == '=') {
+                    tokens.push({ kind: 'less-equals' });
+                    i++;
+                } else {
+                    tokens.push({ kind: 'less-than' });
+                }
+                break;
+            }
+            case '=': {
+                if (source[i + 1] == '=') {
+                    tokens.push({ kind: 'equals-equals' });
+                    i++;
+                } else {
+                    tokens.push({ kind: 'equals' });
+                }
+                break;
+            }
+            case '!': {
+                if (source[i + 1] == '=') {
+                    tokens.push({ kind: 'not-equals' });
+                    i++;
+                } else {
+                    throw new Error(`Unexpected character: ${char}`)
+                }
+                break;
+            }
             case ':': tokens.push({ kind: 'colon' }); break;
             case ';': tokens.push({ kind: 'semicolon' }); break;
             case '\\': tokens.push({ kind: 'backslash' }); break;
+            case '~': tokens.push({ kind: 'tilde' }); break;
             case '|': tokens.push({ kind: 'pipe' }); break;
-            // case '<': tokens.push({ kind: 'less-than' }); break;
-            case '>': tokens.push({ kind: 'greater-than' }); break;
             case ',': tokens.push({ kind: 'comma' }); break;
             case '&': tokens.push({ kind: 'ampersand' }); break;
-            case '_': tokens.push({ kind: 'underscore' }); break;
             case '.': tokens.push({ kind: 'dot' }); break;
             case '@': tokens.push({ kind: 'at' }); break;
 
@@ -164,6 +198,16 @@ export function tokenize(source: string): Token[] {
             case '-': tokens.push({ kind: 'minus' }); break;
             case '*': tokens.push({ kind: 'star' }); break;
             case '/': tokens.push({ kind: 'slash' }); break;
+            case '^': tokens.push({ kind: 'caret' }); break;
+            case '%': tokens.push({ kind: 'percent' }); break;
+
+            // Brackets
+            case '(': tokens.push({ kind: 'open-paren' }); break;
+            case ')': tokens.push({ kind: 'close-paren' }); break;
+            case '{': tokens.push({ kind: 'open-brace' }); break;
+            case '}': tokens.push({ kind: 'close-brace' }); break;
+            case '[': tokens.push({ kind: 'open-bracket' }); break;
+            case ']': tokens.push({ kind: 'close-bracket' }); break;
         }
 
         i++;

src/main.ts

@@ -4,6 +4,7 @@ import { tokenize } from './lexer'
 import { Parser } from './parser'
 import cgCode from './counter.cg?raw';
 import { runApp } from './runtime';
+import { builtins } from './builtins';
 
 const canvas = document.createElement('canvas');
 canvas.width = 800;
@@ -15,7 +16,7 @@ const parser = new Parser(tokens);
 const ast = parser.parse();
 console.log(ast);
 
-const env: Env = new Map();
+const env: Env = new Map(Object.entries(builtins));
 const appRecord = evaluate(ast, env);
 
 console.log(appRecord);

src/parser.ts

@@ -43,18 +43,34 @@ export class Parser {
         const kind = this.current().kind;
         return kind === 'plus' || kind === 'minus' ||
                kind === 'star' || kind === 'slash' ||
-               kind === 'greater-than' || kind === 'ampersand';
-
+               kind === 'percent' || kind === 'caret' ||
+               kind === 'ampersand' ||
+               kind === 'equals-equals' || kind === 'not-equals' ||
+               kind === 'less-than' || kind === 'less-equals' ||
+               kind === 'greater-than' || kind === 'greater-equals' ||
+               kind === 'tilde';
     }
 
     private tokenToOpName(token: Token): string {
         switch (token.kind) {
-            case 'plus': return '+';
-            case 'minus': return '-';
-            case 'star': return '*';
-            case 'slash': return '/';
-            case 'greater-than': return '>';
-            case 'ampersand': return '&';
+            case 'ampersand': return 'cat';
+
+            // Arithmetic
+            case 'plus': return 'add';
+            case 'minus': return 'sub';
+            case 'star': return 'mul';
+            case 'slash': return 'div';
+            case 'percent': return 'mod';
+            case 'caret': return 'pow';
+
+            // Comparison
+            case 'equals-equals': return 'eq';
+            case 'not-equals': return 'neq';
+            case 'greater-than': return 'gt';
+            case 'greater-equals': return 'gte';
+            case 'less-than': return 'lt';
+            case 'less-equals': return 'lte';
+
             default: throw new Error(`Not an operator: ${token.kind}`);
         }
     }
@@ -246,6 +262,18 @@ export class Parser {
 
         while (this.isInfixOp()) {
             const opToken = this.advance();
+
+            if (opToken.kind === 'tilde') {
+                // function application operator
+                const right = this.parseApplication();
+
+                left = {
+                    kind: 'apply',
+                    func: right,
+                    args: [left]
+                };
+            } else {
+                // operators desugar to function calls
                 const opName = this.tokenToOpName(opToken);
                 const right = this.parseApplication();
 
@@ -255,6 +283,7 @@ export class Parser {
                     args: [left, right]
                 }
             }
+        }
 
         return left;
     }

src/types.ts

@@ -39,6 +39,14 @@ export type ConstructorValue = {
     args: Value[]
 }
 
+export type NativeFunction = {
+    kind: 'native'
+    name: string
+    arity: number
+    fn: (...args: Value[]) => Value
+
+}
+
 export type UIValue =
     | { kind: 'rect', w: number, h: number, color: string }
     | { kind: 'text', content: string, x: number, y: number }
@@ -47,4 +55,4 @@ export type UIValue =
     | { kind: 'clickable', child: UIValue, event: string }
     | { kind: 'padding', child: UIValue, amount: number }
 
-export type Value = IntValue | FloatValue | StringValue | Closure | ListValue | RecordValue | ConstructorValue;
+export type Value = IntValue | FloatValue | StringValue | Closure | ListValue | RecordValue | ConstructorValue | NativeFunction;