Initial commit

src/main.ts

@@ -0,0 +1,77 @@
+import './style.css'
+import { SourceText, SourceRegion, sourceText } from 'source-region';
+import type { SourceLocation, Span } from 'source-region';
+
+
+type Expr =
+| { tag: "literal", value: Literal }
+| { tag: "list", values: Expr[] }
+
+namespace Expr {
+  export function number(value: number): Expr {
+    return { tag: "literal", value: { tag: "number", value } };
+  }
+  export function identifier(value: Identifier): Expr {
+    return { tag: "literal", value: { tag: "identifier", value } };
+  }
+  export function list(values: Expr[]): Expr {
+    return { tag: "list", values };
+  }
+
+  export function show(e: Expr): string {
+    switch (e.tag) {
+      case "literal":
+        return showLiteral(e.value);
+      case "list": 
+        return `(${e.values.map(show).join(" ")})`;
+    }
+  }
+
+  function showLiteral(e: Literal): string {
+    switch (e.tag) {
+      case "number":
+        return `${e.value}`;
+      case "identifier":
+        return `${e.value}`;
+    }
+  }
+}
+
+type Literal =
+| { tag: "number", value: number }
+| { tag: "identifier", value: Identifier }
+
+type Identifier = string
+
+
+// === Examples ===
+
+function example00() {
+  const v: Expr = Expr.list([Expr.identifier("f"), Expr.number(123), Expr.number(512)]);
+  console.log(v);
+  console.log(Expr.show(v));
+}
+
+function example01() {
+  const str = `hello, world!
+foo
+bar `;
+
+  const source = sourceText(str);
+  const region = source.fullRegion();
+
+  console.log(region);
+  console.log(region.lineCount);
+  region.forEachLine((span, lineNo) => {
+    console.log(lineNo, region.stringOf(span));
+  });
+}
+
+[
+  example00,
+  example01,
+].forEach((f, i) => {
+  console.log(`====${i}===`);
+  f();
+})
+