walkWhile

fn walkWhile(w: *Walk, node_index: Ast.Node.Index, while_node: Ast.full.While) Error!void

File

Code

fn walkWhile(w: *Walk, node_index: Ast.Node.Index, while_node: Ast.full.While) Error!void {
    // Perform these transformations in this priority order:
    // 1. If the `else` expression is missing or an empty block, replace the condition with `if (true)` if it is not already.
    // 2. If the `then` block is empty, replace the condition with `if (false)` if it is not already.
    // 3. If the condition is `if (true)`, replace the `if` expression with the contents of the `then` expression.
    // 4. If the condition is `if (false)`, replace the `if` expression with the contents of the `else` expression.
    if (!isTrueIdent(w.ast, while_node.ast.cond_expr) and
        (while_node.ast.else_expr == .none or isEmptyBlock(w.ast, while_node.ast.else_expr.unwrap().?)))
    {
        try w.transformations.ensureUnusedCapacity(1);
        w.transformations.appendAssumeCapacity(.{ .replace_with_true = while_node.ast.cond_expr });
    } else if (!isFalseIdent(w.ast, while_node.ast.cond_expr) and isEmptyBlock(w.ast, while_node.ast.then_expr)) {
        try w.transformations.ensureUnusedCapacity(1);
        w.transformations.appendAssumeCapacity(.{ .replace_with_false = while_node.ast.cond_expr });
    } else if (isTrueIdent(w.ast, while_node.ast.cond_expr)) {
        try w.transformations.ensureUnusedCapacity(1);
        w.transformations.appendAssumeCapacity(.{ .replace_node = .{
            .to_replace = node_index,
            .replacement = while_node.ast.then_expr,
        } });
    } else if (isFalseIdent(w.ast, while_node.ast.cond_expr)) {
        try w.transformations.ensureUnusedCapacity(1);
        w.transformations.appendAssumeCapacity(.{ .replace_node = .{
            .to_replace = node_index,
            .replacement = while_node.ast.else_expr.unwrap().?,
        } });
    }

    try walkExpression(w, while_node.ast.cond_expr); // condition

    if (while_node.ast.cont_expr.unwrap()) |cont_expr| {
        try walkExpression(w, cont_expr);
    }

    try walkExpression(w, while_node.ast.then_expr);

    if (while_node.ast.else_expr.unwrap()) |else_expr| {
        try walkExpression(w, else_expr);
    }
}