edit.py

import sys
import os
import re

argc = len(sys.argv)

default_params = "lua_State* L, Udata* G, StackValue* base, Udata* up"

def pln_entry_decl():
    global default_params
    return f"static void function_03({default_params})"

boxfns = """
static Udata *newBox(lua_State *L, Udata *G)
{
    Udata *rec = luaS_newudata(L, sizeof(Box), 0);
    return rec;
}

inline
static Box *box_prims(Udata *u)
{
    char *p = cast_charp(u) + udatamemoffset(0);
    return (Box *) p;
}
"""

t = """
Udata* up = newBox(L, G);
setuvalue(L, s2v(base + 0), up);
luaC_condGC(L, L->top = base + 1, (void)0);
"""


def field_name(n):
    if n <= 9: return f"a0{n}"
    return f"a{n}"

def box_decls(n):
    s = ("typedef struct {\n" + 
            '\n'.join([ f"\tlua_Integer {field_name(i)};" for i in range(1, n + 1) ]) + '\n} Box;\n')
    s += boxfns
    return s


def edit(fname, n):
    """Replace /* Function Prototypes */ with:
    1. The merged upvalue box
    2. The corresponding `prims` and `new_box` function.

    Edit the prototype for `function_03`. That means replacing
    everything inside the brackets as shown below:

    static void function_03( ... );
    with:

    static void function_03(
        lua_State* L, Udata* G, StackValue* base, Udata* up);

    """
    with open(fname, "r") as file:
        c = file.read()

    c = c.replace('/* Function Prototypes */', box_decls(n))
    c = re.sub(r'static void function_03\((.|\n)*?\)', pln_entry_decl(), c)

    c = re.sub(r'crecord_(\d*)_prims\([\d\w]+\)->f\d+', r'box_prims(up)->a\1', c)
    c = re.sub(r'->a0(\d+)1', r'->a\1', c)
    c = c.replace('setuvalue(L, &ccl->upvalue[1], x2);', 'setuvalue(L, &ccl->upvalue[1], up);')

    c = re.sub(r'setuvalue\(L, &ccl->upvalue\[\d*\], x\d+\);', '', c)
    c = re.sub(r'luaF_newCclosure\(L, \d+\)', 'luaF_newCclosure(L, 2)', c);
    c = re.sub(r'uv\d+ = uvalue\(&func->upvalue\[(\d+)\]\);', r'//%uv\1x', c)
    c = c.replace('//%uv1x', 'Udata* up = uvalue(&func->upvalue[1]);');
    c = c.replace('Udata *x2', 'Udata* up');
    c = re.sub(r'Udata \*x\d+;.*', '', c);

    c = re.sub(r'x2 = crecord_\d+_new\(L, G\);', 'up = newBox(L, G);', c)
    c = c.replace('setuvalue(L, s2v(base + 0), x2);', 'setuvalue(L, s2v(base + 0), up);')
    c = c.replace('luaC_condGC(L, L->top = base + 1, (void)0);', '//restore_condGC')
    c = re.sub(r'luaC_condGC\(L, L->top = base \+ \d+, \(void\)0\);', '', c)
    c = c.replace('//restore_condGC', 'luaC_condGC(L, L->top = base + 1, (void)0);')
    c = re.sub(r'(x\d+ = crecord_\d+_new\(L, G\);)', '', c)
    c = re.sub(r'(setuvalue\(L, s2v\(base \+ \d+\), x\d+\);)', '', c)

    c = re.sub(r'Udata \*uv\d+;', '', c)
    c = re.sub(r'function_03\(L, G, L->top,.*\)', 'function_03(L, G, L->top, up)', c)

    with open(fname, "w") as file:
        file.write(c)

if argc != 2:
    print("Usage: edit.py <number of values in the box>")
else:
    fname   = 'temp/out.c'
    nfields = int(sys.argv[1])
    if os.path.isfile(fname):
        edit(fname, nfields)
    else:
        print("File not found")