Class TcbExprTranslator

packages/compiler/src/typecheck/expression.ts:58–417

}

class TcbExprTranslator implements AstVisitor {
  constructor(
    private maybeResolve: (ast: AST) => TcbExpr | null,
    private config: TypeCheckingConfig,
  ) {}

  translate(ast: AST): TcbExpr {
    if (ast instanceof ASTWithSource) {
      ast = ast.ast;
    }

    // First attempt to let any custom resolution logic provide a translation for the given node.
    const resolved = this.maybeResolve(ast);
    if (resolved !== null) {
      return resolved;
    }

    return ast.visit(this);
  }

  visitUnary(ast: Unary): TcbExpr {
    const expr = this.translate(ast.expr);
    const node = new TcbExpr(`${ast.operator}${expr.print()}`);
    return node.wrapForTypeChecker().addParseSpanInfo(ast.sourceSpan);
  }

  visitBinary(ast: Binary): TcbExpr {
    const lhs = this.translate(ast.left);
    const rhs = this.translate(ast.right);
    lhs.wrapForTypeChecker();
    rhs.wrapForTypeChecker();
    const expression = `${lhs.print()} ${ast.operation} ${rhs.print()}`;
    const node = new TcbExpr(
      ast.operation === '??' || ast.operation === '**' ? `(${expression})` : expression,
    );
    node.addParseSpanInfo(ast.sourceSpan);
    return node;
  }

  visitChain(ast: Chain): TcbExpr {
    const elements = ast.expressions.map((expr) => this.translate(expr).print());
    const node = new TcbExpr(elements.join(', '));
    node.wrapForTypeChecker();
    node.addParseSpanInfo(ast.sourceSpan);
    return node;
  }

  visitConditional(ast: Conditional): TcbExpr {
    const condExpr = this.translate(ast.condition);
    const trueExpr = this.translate(ast.trueExp);
    // Wrap `falseExpr` in parens so that the trailing parse span info is not attributed to the
    // whole conditional.
    // In the following example, the last source span comment (5,6) could be seen as the
    // trailing comment for _either_ the whole conditional expression _or_ just the `falseExpr` that
    // is immediately before it:
    // `conditional /*1,2*/ ? trueExpr /*3,4*/ : falseExpr /*5,6*/`
    // This should be instead be `conditional /*1,2*/ ? trueExpr /*3,4*/ : (falseExpr /*5,6*/)`
    const falseExpr = this.translate(ast.falseExp).wrapForTypeChecker();