A python script designed to output jvm descriptors with respect to the standards set by mixin.

jvm_descriptor_generator.py

"""
Implement the descriptor spec defined in Java 16: https://docs.oracle.com/javase/specs/jvms/se16/html/jvms-4.html#jvms-4.3
It is given respect to mixin standards, found at: https://github.com/SpongePowered/Mixin

package com.github.frontear;

class Main {
    private int num;
    private String str;

    public int getNum() {
        return num;
    }

    public void setNum(int num) {
        this.num = num;
    }

    public String getStr() {
        return str;
    }

    public void setStr(String str) {
        this.str = str;
    }
}

---

Lcom/github/frontear/Main;num:I
Lcom/github/frontear/Main;str:Ljava/lang/String;

Lcom/github/frontear/Main;getNum()I
Lcom/github/frontear/Main;setNum(I)V
Lcom/github/frontear/Main;getStr()Ljava/lang/String;
Lcom/github/frontear/Main;setStr(Ljava/lang/String;)V
"""

PRIMITIVES = {
    "boolean": "Z",
    "double": "D",
    "float": "F",
    "short": "S",
    "byte": "B",
    "char": "C",
    "long": "J",
    "void": "V",
    "int": "I",
}

def type_desc(name, arr_dim = 0):
    type = None

    if (n := name.lower()) in PRIMITIVES:
        type = PRIMITIVES[n]
    else:
        type = f"L{name.replace('.', '/')};"

    if arr_dim > 0:
        type = arr_dim * "[" + type

    return type

def class_desc(package, name):
    return type_desc(f"{package}.{name}")

def field_desc(class_desc, name, type_desc):
    return f"{class_desc}{name}:{type_desc}"

def method_desc(class_desc, name, type_desc, *param_desc):
    return f"{class_desc}{name}({''.join(param_desc)}){type_desc}"

def main():
    c = class_desc("com.github.frontear", "Main")
    s = type_desc("java.lang.String")
    v = type_desc("void")
    i = type_desc("int")

    print(field_desc(c, "num", i))
    print(field_desc(c, "str", s))
    print()
    print(method_desc(c, "getNum", i))
    print(method_desc(c, "setNum", v, i))
    print(method_desc(c, "getStr", s))
    print(method_desc(c, "setStr", v, s))

if __name__ == "__main__":
    main()