pt-lisp/implementations/js/printer.js

import { DataTypes } from './datatypes.js';
import { Env } from './env.js';

export class Printer {
    static princToString(sexp) {
	if (sexp.type === DataTypes.Cons) {
	    if (sexp.car.type === DataTypes.Symbol &&
		['QUOTE', 'QUASIQUOTE', 'UNQUOTE', 'UNQUOTE-SPLICING'].includes(sexp.car.value)) {
		let prefix = '';
		switch (sexp.car.value) {
		case 'QUOTE': prefix = '\''; break;
		case 'QUASIQUOTE': prefix = '`'; break;
		case 'UNQUOTE': prefix = ','; break;
		case 'UNQUOTE-SPLICING': prefix = ',@'; break;
		}
		return prefix + Printer.princToString(sexp.cdr.car);
	    } else {
		let result = Printer.princToString(sexp.car);
		if (sexp.cdr.type !== DataTypes.Nil && sexp.cdr.type === DataTypes.Cons) {
		    let s = Printer.princToString(sexp.cdr);
		    result += ' ' + s.substr(1, s.length - 2);
		} else if (sexp.cdr.type !== DataTypes.Nil) {
		    result += ' . ' + Printer.princToString(sexp.cdr);
		}
		return '(' + result.trim() + ')';
	    }
	}
	switch(sexp.type) {
	case DataTypes.String: 
	    // return `"${sexp.value}"`;
	    return `${sexp.value}`;
	case DataTypes.Symbol:
	    return sexp.value.toUpperCase();
	case DataTypes.Number:
	    return `${sexp.value}`;
	case DataTypes.Function:
	    return `<FUNCTION ${sexp.value}>`;
	case DataTypes.True:
	    return 'T';
	case DataTypes.Nil:
	    return 'NIL';
	}
    }

    static prin1ToString(sexp) {
	if (sexp.type === DataTypes.Cons) {
	    if (sexp.car.type === DataTypes.Symbol &&
		['QUOTE', 'QUASIQUOTE', 'UNQUOTE', 'UNQUOTE-SPLICING'].includes(sexp.car.value)) {
		let prefix = '';
		switch (sexp.car.value) {
		case 'QUOTE': prefix = '\''; break;
		case 'QUASIQUOTE': prefix = '`'; break;
		case 'UNQUOTE': prefix = ','; break;
		case 'UNQUOTE-SPLICING': prefix = ',@'; break;
		}
		return prefix + Printer.princToString(sexp.cdr.car);
	    } else {
		let result = Printer.princToString(sexp.car);
		if (sexp.cdr.type !== DataTypes.Nil && sexp.cdr.type === DataTypes.Cons) {
		    let s = Printer.princToString(sexp.cdr);
		    result += ' ' + s.substr(1, s.length - 2);
		} else if (sexp.cdr.type !== DataTypes.Nil) {
		    result += ' . ' + Printer.princToString(sexp.cdr);
		}
		return '(' + result.trim() + ')';
	    }
	}
	switch(sexp.type) {
	case DataTypes.String: 
	    return `"${sexp.value}"`;
	case DataTypes.Symbol:
	    return sexp.value.toUpperCase();
	case DataTypes.Number:
	    return `${sexp.value}`;
	case DataTypes.Function:
	    return `<FUNCTION ${sexp.value}>`;
	case DataTypes.True:
	    return 'T';
	case DataTypes.Nil:
	    return 'NIL';
	}
    }

    static princ(sexp, env) {
	Env.get(env, 'STANDARD-OUTPUT-STREAM').pushData(Printer.princToString(sexp)/*.trim()*/);
    }

    static print(sexp, env) {
	Env.get(env, 'STANDARD-OUTPUT-STREAM').pushData('\n');
	Printer.princ(sexp, env);
    }

    static prin1(sexp, env) {
	Env.get(env, 'STANDARD-OUTPUT-STREAM').pushData(Printer.prin1ToString(sexp)/*.trim()*/);
    }
}