Get prelude working

The “externalSyms” argument, defaulting to “globals”, for ArkState.run() is
now an ArkObject.

Return an object from prelude.ursa, and, in the front-end, merge it into
‘globals’ before executing code.

TODO.md

@@ -2,7 +2,6 @@
 
 ## Version 0.2
 
-* `range()` iterator, written in Ursa (start of stdlib/prelude).
 * Sets: use `{ Exp, }` notation, with mandatory first comma.
 * Map interface to file system and internet.
 

package.json

@@ -46,7 +46,7 @@
   "scripts": {
     "lint": "eslint . --ext .ts && depcheck",
     "prebuild": "node --print \"'export default \\'' + require('./package.json').version + '\\';'\" > src/version.ts",
-    "build": "tsc --build",
+    "build": "tsc --build && cp src/prelude.ursa lib/",
     "clean": "tsc --build --clean",
     "test": "npm run build && ava",
     "test-ursa": "ava src/ursa/ursa.test.ts",

src/cli.ts

@@ -4,13 +4,14 @@
 
 import path from 'path'
 import fs, {PathOrFileDescriptor} from 'fs'
+import {fileURLToPath} from 'url'
 import * as readline from 'node:readline'
 import {ArgumentParser, RawDescriptionHelpFormatter} from 'argparse'
 import assert from 'assert'
 
 import {
   debug, ArkState, toJs,
-  ArkUndefined, ArkList, ArkValRef, ArkString, globals,
+  ArkUndefined, ArkNull, ArkObject, ArkList, ArkValRef, ArkString, globals,
   Environment, PartialCompiledArk, compile as arkCompile, serializeVal,
 } from '@ursalang/ark'
 
@@ -142,6 +143,15 @@ async function main() {
         source = source.substring(source.indexOf('\n'))
       }
     }
+    const thisDir = path.dirname(fileURLToPath(import.meta.url))
+    const prelude = ursaCompile(
+      fs.readFileSync(path.join(thisDir, 'prelude.ursa'), {encoding: 'utf-8'}),
+    )
+    const ark = new ArkState()
+    const preludeObj = prelude.value.eval(ark) as ArkObject
+    for (const [sym, val] of preludeObj.val) {
+      globals.set(sym, new ArkValRef(val))
+    }
     if (args.compile) {
       if (source === undefined) {
         throw new Error('--compile given, but nothing to compile')
@@ -158,7 +168,7 @@ async function main() {
       // Run the program
       let result
       if (source !== undefined) {
-        result = runWithTraceback(new ArkState(), compile(source))
+        result = runWithTraceback(ark, compile(source))
       }
       if (source === undefined || args.interactive) {
         result = await repl()

src/compiler.ts

@@ -829,7 +829,7 @@ export function compile(
   const ast = semantics(matchResult)
   const compiled = ast.toAST(env, false, false, false)
   const freeVars = ast.freeVars(env)
-  env.externalSyms.forEach((_val, id) => freeVars.delete(id))
+  env.externalSyms.val.forEach((_val, id) => freeVars.delete(id))
   return new PartialCompiledArk(compiled, freeVars, ast.boundVars)
 }
 

src/prelude.ursa

@@ -3,12 +3,12 @@
 // Released under the MIT license.
 
 // Range iterator.
-let range = fn(n) {
-  let i = 0
-  fn() {
-    i := i + 1
-    if i <= n { i - 1 } else { null }
+{
+  range: fn(n) {
+    let i = 0
+    fn() {
+      i := i + 1
+      if i <= n { i - 1 } else { null }
+    }
   }
 }
-
-;