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✨ start working on parser

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DrMaxNix 2022-09-08 21:16:21 +02:00
parent 06a9d4a122
commit d52cdc4874
1 changed files with 456 additions and 4 deletions
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460
src/parser.js
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@ -15,9 +15,461 @@ class Juicescript_parser {
MAIN: Do parsing MAIN: Do parsing
*/ */
parse(){ parse(){
/**/for(let one_token of this.token_list){ // RESET //
/**/one_token.type = Juicescript.token_type.name(one_token.type); // counters
/**/console.log(one_token); this.position = 0;
/**/}
// current scope
this.scope = null;
// token list
this.tree = this.program_tree_template();
// warning and error counter
this.warning_count = 0;
this.error_count = 0;
// PARSE ALL TOKENS //
while(!this.is_at_end()){
// consume next token
this.next();
// parse
this.parse_one();
}
// RETURN PROGRAM TREE //
return this.tree;
}
/*
HELPER: Parse one token at current position
*/
parse_one(){
switch(this.token.type){
// DELIMITER //
case Juicescript.token_type.DELIMITER:
// ignore
break;
// FUNCTION DEFINITION //
case Juicescript.token_type.DEF:
this.parse_def();
break;
// END //
case Juicescript.token_type.END:
this.parse_end();
break;
// COMMAND //
case Juicescript.token_type.IDENTIFIER:
this.parse_command();
break;
// EVERYTHING ELSE //
default:
// unexpected (ignore with error)
this.error_token("unexpected token");
break;
}
}
/*
PARSER: Handle function definition
*/
parse_def(){
let parameter_list = [];
while(!this.is_at_end()){
// IS NEXT TOKEN A DELIMITER? //
if(this.match_type(Juicescript.token_type.DELIMITER)){
// end of parameter list
break;
}
// GET NEXT PARAMETER //
// consume next token
this.next();
/**/continue;
// make sure next has valid type for parameter
if(!this.is_parameter(this.token)){
// ignore with error
this.error_token("invalid parameter");
continue;
}
// PARSE PARAMETER //
// get parsed object
let parameter = this.parse_parameter();
// add to list
parameter_list.push(parameter);
}
/**/console.log(parameter_list);
/**/this.debug("enter scope " + this.peek().value);
/**/this.scope = this.peek().value;
/**/this.tree.scope[this.scope] = this.scope_tree_template();
}
/*
PARSER: Handle function definition
*/
parse_end(){
/**/this.debug("enter scope root");
/**/this.scope = null;
}
/*
PARSER: Handle command
*/
parse_command(){
let argument_list = [];
while(!this.is_at_end()){
// IS NEXT TOKEN A DELIMITER? //
if(this.match_type(Juicescript.token_type.DELIMITER)){
// end of argument list
break;
}
// GET NEXT ARGUMENT //
// consume next token
this.next();
// make sure next has valid type for an argument
if(!this.is_argument(this.token)){
// ignore with error
this.error_token("invalid argument");
continue;
}
// PARSE ARGUMENT //
// get parsed object
let argument = this.parse_argument();
// add to list
argument_list.push(argument);
}
/**/console.log(argument_list);
///**/this.command_add({name: this.token.value});
}
/*
PARSER: Handle argument at current position and return resulting object
*/
parse_argument(){
// NEW OJECT //
let argument = {};
// VARIABLE OR LITERAL? //
if(this.is_variable(this.token)){
// parse variable
let variable = this.parse_variable();
// add to list
argument = {type: Juicescript.argument_type.VARIABLE, variable: variable};
} else {
// add literal
argument = {type: Juicescript.argument_type.LITERAL, value: this.token.value};
}
// RETURN //
return argument;
}
/*
PARSER: Handle variable at current position and return resulting object
*/
parse_variable(){
// NEW OJECT //
let variable = {};
// clear index list
variable.index = [];
// GET VARIABLE NAME //
if(this.token.value !== null){
// literal
variable.name = {type: Juicescript.argument_type.LITERAL, value: this.token.value};
} else if(this.match_type(Juicescript.token_type.BRACKET_CURLY_OPEN)){
// consume argument
this.next();
// make sure token has valid type for an argument
if(this.is_argument(this.token)){
// value of another variable
let argument = this.parse_argument();
variable.name = argument;
} else {
// ignore with error
this.error_token("expected variable name, but got");
}
// consume curly closing bracket
if(!this.match_type(Juicescript.token_type.BRACKET_CURLY_CLOSE)){
// ignore with error
this.error_token("expected '}', but got", this.peek());
}
} else {
// ignore with error
this.error("unable to determine variable name");
}
// HANDLE OPTIONAL LIST KEYS //
while(this.match_type(Juicescript.token_type.BRACKET_SQUARE_OPEN)){
// consume argument
this.next();
// make sure token has valid type for an argument
if(this.is_argument(this.token)){
// parse argument
let argument = this.parse_argument();
// add index to list
variable.index.push(argument);
} else {
// ignore with error
this.error_token("expected list index, but got");
}
// consume square closing bracket
if(!this.match_type(Juicescript.token_type.BRACKET_SQUARE_CLOSE)){
// ignore with error
this.error_token("expected ']', but got", this.peek());
}
}
// RETURN //
return variable;
}
/*
HELPER: Consume next token from list
*/
next(){
this.token = this.token_list[this.position++];
return this.token;
}
/*
HELPER: Return OFFSET next token from list
*/
peek(offset = 0){
return this.token_list[(this.position + offset)];
}
/*
HELPER: Consume (and return true) if OFFSET next token's type matches TYPE
*/
match_type(type, offset = 0){
// ignore if it doesn't match
if(this.peek(offset).type != type) return false;
// consume if it matches
this.position += offset;
this.next();
return true;
}
match_type_list(type_list, offset = 0){
// check all types
for(var one_type of type_list){
// check this type
if(this.match_type(one_type, offset)) return true;
}
// nothing found
return false;
}
/*
HELPER: Return if we are at end of token list
*/
is_at_end(){
// check if next token is of type eof
let eof = (this.peek().type === Juicescript.token_type.EOF);
// check if next token exists
let out_of_tokens = (this.token_list.length <= this.position);
// if one of those is true, we are at the end
return (eof || out_of_tokens);
}
/*
HELPER: Check if type of TOKEN is valid for arguments
*/
is_argument(token){
// check lookup table
return ([
Juicescript.token_type.VARIABLE,
Juicescript.token_type.STRING,
Juicescript.token_type.NUMBER,
Juicescript.token_type.TRUE,
Juicescript.token_type.FALSE,
Juicescript.token_type.NULL
]).includes(token.type);
}
/*
HELPER: Check if TOKEN is a variable
*/
is_variable(token){
return (token.type === Juicescript.token_type.VARIABLE);
}
/*
HELPER: Add new command object with OPTIONS to current scope
*/
command_add(options){
// NEW OJECT //
let command = {};
// COLLECT REQUIRED ATTRIBUTES //
// name
command.name = options.name ?? null;
if(command.name === null){
throw "missing command name";
}
// COLLECT ATTRIBUTES WITH POSSIBLE FALLBACK VALUES //
// line
command.line = options.line ?? this.token.line;
// OPTIONAL ATTRIBUTES //
command.argument = options.argument ?? [];
// ADD TO SCOPE'S COMMAND LIST //
/**/this.debug("add command " + command.name + " to scope " + (this.scope ?? "root"));
/**/console.log(this.scope, command);
/**/let scope_command_list = (this.scope === null ? this.tree.root.command : this.tree.scope[this.scope].command);
/**/scope_command_list ??= [];
/**/scope_command_list.push(command);
//*/ TODO
}
/*
HELPER: Return empty program tree structure
*/
program_tree_template(){
return {
root: {
command: [],
flag: {}
},
scope: {}
};
}
/*
HELPER: Return empty scope tree structure
*/
scope_tree_template(){
return {
command: [],
flag: {},
global: []
};
}
/*
HELPER: Automagically produce error messages
*/
error_token(text, token = null){
// GET TOKEN //
token ??= this.token;
// HANDLE TOKEN //
// get token type name
let type_name = Juicescript.token_type.name(token.type).toLowerCase();
// try to get lexeme
let lexeme = null;
if(token.lexeme.trim().length > 0){
lexeme = token.lexeme.trim();
}
// construct error message
this.error(text + " " + (lexeme === null ? type_name : ("'" + lexeme + "'")));
}
/*
HELPER: Automagically keep track of problems and add additional info to stderr
*/
debug(text, additional){
// add defaults
additional ??= {};
additional.line ??= this.token.line;
// forward
this.io.stderr.debug(text, additional);
}
info(text, additional){
// add defaults
additional ??= {};
additional.line ??= this.token.line;
// forward
this.io.stderr.info(text, additional);
}
warning(text, additional){
// KEEP TRACK OF PROBLEM //
this.warning_count++;
// PRINT MESSAGE //
// add defaults
additional ??= {};
additional.line ??= this.token.line;
// forward
this.io.stderr.warning(text, additional);
}
error(text, additional){
// KEEP TRACK OF PROBLEM //
this.error_count++;
// PRINT MESSAGE //
// add defaults
additional ??= {};
additional.line ??= this.token.line;
// forward
this.io.stderr.error(text, additional);
} }
} }