import Node from '../core/Node.js';
import { expression } from '../code/ExpressionNode.js';
import { nodeObject, nodeArray } from '../tsl/TSLBase.js';
/** @module LoopNode **/
/**
* This module offers a variety of ways to implement loops in TSL. In it's basic form it's:
* ```js
* Loop( count, ( { i } ) => {
*
* } );
* ```
* However, it is also possible to define a start and end ranges, data types and loop conditions:
* ```js
* Loop( { start: int( 0 ), end: int( 10 ), type: 'int', condition: '<' }, ( { i } ) => {
*
* } );
*```
* Nested loops can be defined in a compacted form:
* ```js
* Loop( 10, 5, ( { i, j } ) => {
*
* } );
* ```
* Loops that should run backwards can be defined like so:
* ```js
* Loop( { start: 10 }, () => {} );
* ```
* The module also provides `Break()` and `Continue()` TSL expression for loop control.
* @augments Node
*/
class LoopNode extends Node {
static get type() {
return 'LoopNode';
}
/**
* Constructs a new loop node.
*
* @param {Array<Any>} params - Depending on the loop type, array holds different parameterization values for the loop.
*/
constructor( params = [] ) {
super();
this.params = params;
}
/**
* Returns a loop variable name based on an index. The pattern is
* `0` = `i`, `1`= `j`, `2`= `k` and so on.
*
* @param {Number} index - The index.
* @return {String} The loop variable name.
*/
getVarName( index ) {
return String.fromCharCode( 'i'.charCodeAt( 0 ) + index );
}
/**
* Returns properties about this node.
*
* @param {NodeBuilder} builder - The current node builder.
* @return {Object} The node properties.
*/
getProperties( builder ) {
const properties = builder.getNodeProperties( this );
if ( properties.stackNode !== undefined ) return properties;
//
const inputs = {};
for ( let i = 0, l = this.params.length - 1; i < l; i ++ ) {
const param = this.params[ i ];
const name = ( param.isNode !== true && param.name ) || this.getVarName( i );
const type = ( param.isNode !== true && param.type ) || 'int';
inputs[ name ] = expression( name, type );
}
const stack = builder.addStack(); // TODO: cache() it
properties.returnsNode = this.params[ this.params.length - 1 ]( inputs, stack, builder );
properties.stackNode = stack;
builder.removeStack();
return properties;
}
/**
* This method is overwritten since the node type is inferred based on the loop configuration.
*
* @param {NodeBuilder} builder - The current node builder.
* @return {String} The node type.
*/
getNodeType( builder ) {
const { returnsNode } = this.getProperties( builder );
return returnsNode ? returnsNode.getNodeType( builder ) : 'void';
}
setup( builder ) {
// setup properties
this.getProperties( builder );
}
generate( builder ) {
const properties = this.getProperties( builder );
const params = this.params;
const stackNode = properties.stackNode;
for ( let i = 0, l = params.length - 1; i < l; i ++ ) {
const param = params[ i ];
let start = null, end = null, name = null, type = null, condition = null, update = null;
if ( param.isNode ) {
type = 'int';
name = this.getVarName( i );
start = '0';
end = param.build( builder, type );
condition = '<';
} else {
type = param.type || 'int';
name = param.name || this.getVarName( i );
start = param.start;
end = param.end;
condition = param.condition;
update = param.update;
if ( typeof start === 'number' ) start = builder.generateConst( type, start );
else if ( start && start.isNode ) start = start.build( builder, type );
if ( typeof end === 'number' ) end = builder.generateConst( type, end );
else if ( end && end.isNode ) end = end.build( builder, type );
if ( start !== undefined && end === undefined ) {
start = start + ' - 1';
end = '0';
condition = '>=';
} else if ( end !== undefined && start === undefined ) {
start = '0';
condition = '<';
}
if ( condition === undefined ) {
if ( Number( start ) > Number( end ) ) {
condition = '>=';
} else {
condition = '<';
}
}
}
const internalParam = { start, end, condition };
//
const startSnippet = internalParam.start;
const endSnippet = internalParam.end;
let declarationSnippet = '';
let conditionalSnippet = '';
let updateSnippet = '';
if ( ! update ) {
if ( type === 'int' || type === 'uint' ) {
if ( condition.includes( '<' ) ) update = '++';
else update = '--';
} else {
if ( condition.includes( '<' ) ) update = '+= 1.';
else update = '-= 1.';
}
}
declarationSnippet += builder.getVar( type, name ) + ' = ' + startSnippet;
conditionalSnippet += name + ' ' + condition + ' ' + endSnippet;
updateSnippet += name + ' ' + update;
const forSnippet = `for ( ${ declarationSnippet }; ${ conditionalSnippet }; ${ updateSnippet } )`;
builder.addFlowCode( ( i === 0 ? '\n' : '' ) + builder.tab + forSnippet + ' {\n\n' ).addFlowTab();
}
const stackSnippet = stackNode.build( builder, 'void' );
const returnsSnippet = properties.returnsNode ? properties.returnsNode.build( builder ) : '';
builder.removeFlowTab().addFlowCode( '\n' + builder.tab + stackSnippet );
for ( let i = 0, l = this.params.length - 1; i < l; i ++ ) {
builder.addFlowCode( ( i === 0 ? '' : builder.tab ) + '}\n\n' ).removeFlowTab();
}
builder.addFlowTab();
return returnsSnippet;
}
}
export default LoopNode;
/**
* TSL function for creating a loop node.
*
* @function
* @param {...Any} params - A list of parameters.
* @returns {LoopNode}
*/
export const Loop = ( ...params ) => nodeObject( new LoopNode( nodeArray( params, 'int' ) ) ).append();
/**
* TSL function for creating a `Continue()` expression.
*
* @function
* @returns {ExpressionNode}
*/
export const Continue = () => expression( 'continue' ).append();
/**
* TSL function for creating a `Break()` expression.
*
* @function
* @returns {ExpressionNode}
*/
export const Break = () => expression( 'break' ).append();
// Deprecated
/**
* @function
* @deprecated since r168. Use {@link Loop} instead.
*
* @param {...any} params
* @returns {LoopNode}
*/
export const loop = ( ...params ) => { // @deprecated, r168
console.warn( 'TSL.LoopNode: loop() has been renamed to Loop().' );
return Loop( ...params );
};