/**
         
 * Modern Albufeira Prolog Interpreter
         
 *
         
 * Warranty & Liability
         
 * To the extent permitted by applicable law and unless explicitly
         
 * otherwise agreed upon, XLOG Technologies AG makes no warranties
         
 * regarding the provided information. XLOG Technologies AG assumes
         
 * no liability that any problems might be solved with the information
         
 * provided by XLOG Technologies AG.
         
 *
         
 * Rights & License
         
 * All industrial property rights regarding the information - copyright
         
 * and patent rights in particular - are the sole property of XLOG
         
 * Technologies AG. If the company was not the originator of some
         
 * excerpts, XLOG Technologies AG has at least obtained the right to
         
 * reproduce, change and translate the information.
         
 *
         
 * Reproduction is restricted to the whole unaltered document. Reproduction
         
 * of the information is only allowed for non-commercial uses. Selling,
         
 * giving away or letting of the execution of the library is prohibited.
         
 * The library can be distributed as part of your applications and libraries
         
 * for execution provided this comment remains unchanged.
         
 *
         
 * Restrictions
         
 * Only to be distributed with programs that add significant and primary
         
 * functionality to the library. Not to be distributed with additional
         
 * software intended to replace any components of the library.
         
 *
         
 * Trademarks
         
 * Jekejeke is a registered trademark of XLOG Technologies AG.
         
 */
         

         
import {exec_build, check_integer, add, check_number, 
         
    narrow_float, check_atom, make_check,
         
    exec_unify, Compound, make_error, deref
         
} from "../../dogelog.mjs";
         

         

         
function test_sys_float_atom(args) {
         
    let value = deref(exec_build(args[0]));
         
    check_number(value);
         
    let spec = deref(exec_build(args[1]));
         
    check_atom(spec);
         
    let digs = deref(exec_build(args[2]));
         
    check_integer(digs);
         
    if (digs < 0)
         
        throw make_error(new Compound("domain_error",
         
            ["not_less_than_zero", digs]));
         
    let text;
         
    value = narrow_float(value);
         
    if (spec === "f") {
         
        text = value.toFixed(digs);
         
        text = shape_float(text, 0);
         
    } else if (spec === "e") {
         
        text = value.toExponential(digs);
         
        text = shape_float(text, 0);
         
    } else if (spec === "g") {
         
        text = value.toPrecision(digs);
         
        text = shape_float(text, 2);
         
    } else {
         
        throw make_error(new Compound("domain_error",
         
            ["illegal_format", spec]));
         
    }
         
    return exec_unify(args[3], text);
         
}
         

         
function shape_float(res, flag) {
         
    let peek = res.indexOf("e");
         
    if (peek !== -1) {
         
        res = shape_float_mantissa(res.slice(0, peek), flag) +
         
            "e" + shape_float_exponent(res.slice(peek+1));
         
    } else {
         
        res = shape_float_mantissa(res, flag);
         
    }
         
    return res;
         
}
         

         
function shape_float_mantissa(res, flag) {
         
    if ((flag & 2) !== 0) {
         
        if (res.indexOf(".") !== -1) {
         
            let pos = res.length;
         
            while (res.codePointAt(pos - 1) === 48)  // '0'
         
                pos--;
         
            if (res.charCodeAt(pos - 1) === 46)  // '.'
         
                pos--;
         
            if (pos !== res.length)
         
                res = res.slice(0, pos);
         
        }
         
    }
         
    return res;
         
}
         

         
function shape_float_exponent(res) {
         
    if (0 < res.length && res.charCodeAt(0) === 43)  // '+'
         
        res = res.slice(1);
         
    return res;
         
}
         

         

         
export function main() {
         
    add("sys_float_atom", 4, make_check(test_sys_float_atom));
         
}