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pub use super::node::{Attrs, Node};
//use crate::generator::TestManager;
//use crate::TEST;
use crate::{Error, Result};
use std::fmt;
/// An AST provides an API for constructing a node tree, when completed it can be unwrapped
/// to a node by calling the unwrap() method
#[derive(Clone)]
pub struct AST<T> {
nodes: Vec<Node<T>>,
}
impl<T: Attrs> AST<T> {
/// Create a new AST with the given node as the top-level
pub fn new() -> AST<T> {
AST { nodes: vec![] }
}
/// Consumes the AST, converting it to a Node
pub fn unwrap(&mut self) -> Node<T> {
while self.nodes.len() > 1 {
let n = self.nodes.pop().unwrap();
if let Some(node) = self.nodes.last_mut() {
node.add_child(n);
}
}
self.nodes.pop().unwrap()
}
/// Push a new terminal node into the AST
pub fn push(&mut self, node: Node<T>) {
match self.nodes.last_mut() {
Some(n) => n.add_child(node),
None => self.nodes.push(node),
}
}
pub fn append(&mut self, nodes: &mut Vec<Node<T>>) {
match self.nodes.last_mut() {
Some(n) => {
n.add_children(nodes.to_vec());
}
None => self.nodes.append(nodes),
}
}
/// Push a new node into the AST and leave it open, meaning that all new nodes
/// added to the AST will be inserted as children of this node until it is closed.
/// A reference ID is returned and the caller should save this and provide it again
/// when calling close(). If the reference does not match the expected an error will
/// be raised. This will catch any cases of AST application code forgetting to close
/// a node before closing one of its parents.
pub fn push_and_open(&mut self, node: Node<T>) -> usize {
self.nodes.push(node);
self.nodes.len()
}
/// Close the currently open node
pub fn close(&mut self, ref_id: usize) -> Result<()> {
if self.nodes.len() != ref_id {
return Err(Error::new(&format!(
"Attempt to close a parent AST node without first closing all its children (given ID: {}, current length: {}), it looks like you have either forgotten to close an open node or given the wrong reference ID",
ref_id, self.nodes.len()
)));
}
if ref_id == 1 {
return Err(Error::new("The top-level AST node can never be closed"));
}
let n = self.nodes.pop().unwrap();
if let Some(node) = self.nodes.last_mut() {
node.add_child(n);
}
Ok(())
}
/// Replace the node n - offset with the given node, use offset = 0 to
/// replace the last node that was pushed.
/// Fails if the AST has no children yet or if the offset is otherwise out
/// of range.
pub fn replace(&mut self, node: Node<T>, mut offset: usize) -> Result<()> {
let mut node_offset = 0;
let mut child_offset = 0;
let mut root_node = false;
let node_len = self.nodes.len();
while offset > 0 {
let node = &self.nodes[node_len - 1 - node_offset];
let num_children = node.children.len();
// If node to be replaced lies in this node's children
if num_children > offset {
child_offset = offset;
offset = 0;
// If node to be replaced is this node itself
} else if num_children == offset {
root_node = true;
offset = 0;
// The node to be replaced lies outside this node
} else {
node_offset += 1;
offset -= num_children + 1;
child_offset = 0;
}
}
let index = node_len - 1 - node_offset;
let mut n = self.nodes.remove(index);
if root_node {
self.nodes.insert(index, node);
} else {
n.replace_child(node, child_offset)?;
self.nodes.insert(index, n);
}
Ok(())
}
/// Insert the node at position n - offset, using offset = 0 is equivalent
/// calling push().
pub fn insert(&mut self, node: Node<T>, mut offset: usize) -> Result<()> {
let mut node_offset = 0;
let mut child_offset = 0;
let node_len = self.nodes.len();
while offset > 0 {
let node = &self.nodes[node_len - 1 - node_offset];
let num_children = node.children.len();
// If node is to be inserted into this node's children
if num_children >= offset {
child_offset = offset;
offset = 0;
// The parent node lies outside this node
} else {
node_offset += 1;
offset -= num_children + 1;
child_offset = 0;
}
}
let index = node_len - 1 - node_offset;
let mut n = self.nodes.remove(index);
n.insert_child(node, child_offset)?;
self.nodes.insert(index, n);
Ok(())
}
/// Returns a copy of node n - offset, an offset of 0 means
/// the last node pushed.
/// Fails if the offset is out of range.
pub fn get(&self, mut offset: usize) -> Result<Node<T>> {
let mut node_offset = 0;
let mut child_offset = 0;
let mut root_node = false;
let node_len = self.nodes.len();
while offset > 0 {
let node = &self.nodes[node_len - 1 - node_offset];
let num_children = node.children.len();
// If node to be returned lies in this node's children
if num_children > offset {
child_offset = offset;
offset = 0;
// If node to be returned is this node itself
} else if num_children == offset {
root_node = true;
offset = 0;
// The node to be returned lies outside this node
} else {
node_offset += 1;
offset -= num_children + 1;
child_offset = 0;
}
}
let index = node_len - 1 - node_offset;
let n = &self.nodes[index];
if root_node {
Ok(self.nodes[index].clone())
} else {
Ok(n.get_child(child_offset)?)
}
}
pub fn get_with_descendants(&self, offset: usize) -> Result<Node<T>> {
let mut cnt: usize = 0;
for n in self.nodes.iter().rev() {
if let Some(node) = n.get_descendant(offset, &mut cnt) {
return Ok(node);
}
}
Err(Error::new(&format!(
"Offset {} is out of range of the current AST",
offset
)))
}
/// Clear the current AST and start a new one with the given node at the top-level
pub fn start(&mut self, node: Node<T>) {
self.nodes.clear();
self.nodes.push(node);
}
pub fn process(
&self,
process_fn: &mut dyn FnMut(&Node<T>) -> Result<Node<T>>,
) -> Result<Node<T>> {
if self.nodes.len() > 1 {
let node = self.to_node();
process_fn(&node)
} else {
process_fn(&self.nodes[0])
}
}
/// Execute the given function which receives the a reference to the AST (as a Node) as
/// its input, returning the result of the function
pub fn with_node<N, F>(&self, mut process_fn: F) -> Result<N>
where
F: FnMut(&Node<T>) -> Result<N>,
{
if self.nodes.len() > 1 {
let node = self.to_node();
process_fn(&node)
} else {
process_fn(&self.nodes[0])
}
}
pub fn to_string(&self) -> String {
if self.nodes.len() > 1 {
let node = self.to_node();
node.to_string()
} else {
self.nodes[0].to_string()
}
}
/// Serializes the AST for import into Python
pub fn to_pickle(&self) -> Vec<u8> {
if self.nodes.len() > 1 {
let node = self.to_node();
node.to_pickle()
} else {
self.nodes[0].to_pickle()
}
}
/// Writes the AST to the given file to allow it to be reviewed for debugging purposes
pub fn to_file<P: AsRef<std::path::Path>>(&self, path: P) -> Result<()> {
self.to_node().to_file(path)
}
/// Clones the current state of the AST into a Node, leaving the AST unmodified
pub fn to_node(&self) -> Node<T> {
let mut node = self.nodes.last().unwrap().clone();
let num = self.nodes.len();
if num > 1 {
for i in 1..num {
let n = node;
node = self.nodes[num - i - 1].clone();
node.add_child(n);
}
}
node
}
}
impl<T> fmt::Display for AST<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.to_string())
}
}
impl<T> fmt::Debug for AST<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}", self.to_string())
}
}
impl<T: Attrs> PartialEq<Node<T>> for AST<T> {
fn eq(&self, node: &Node<T>) -> bool {
self.to_node() == *node
}
}