path: root/src/parser.h

#ifndef INCLUDE_parser
#define INCLUDE_parser

#include "ast.h"
#include "lexer.h"
#include "token.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


typedef struct {
  _LX *lx;
  _T cur;
} _P;


static void perror_expected(_LX *lx, const char *expected, const char *got) {
  fprintf(stderr, "[PARSER] Error at line %d, column %d: expected %s, got %s\n", 
          lx->line, lx->col, expected, got);
  exit(1);
}

static void perror_unexpected(_LX *lx, const char *context, const char *got) {
  fprintf(stderr, "[PARSER] Error at line %d, column %d: unexpected %s in %s\n", 
          lx->line, lx->col, got, context);
  exit(1);
}

static void pnext(_P *p) {
  if (p->cur.lxem) {
    free(p->cur.lxem);
    p->cur.lxem = NULL;
  }
  p->cur = lxnext(p->lx);
}


static void pexpect(_P *p, _TK tk) {
  if (p->cur.kind != tk) {
    const char *got = (p->cur.kind < TK__COUNT) ? _TN[p->cur.kind] : "<?>";
    perror_expected(p->lx, _TN[tk], got);
  }
}


static int is_type_token(_TK k) {
  return k == TK_INT || k == TK_CHAR || k == TK_VOID ||
         k == TK_FLOAT || k == TK_LONG || k == TK_SHORT;
}


static _TY pparse_type(_P *p) {
  _TY ty;
  switch (p->cur.kind) {
    case TK_INT:   ty = (_TY){.base=TY_INT,  .ptr_level=0,.array_size=-1}; break;
    case TK_CHAR:  ty = (_TY){.base=TY_CHAR, .ptr_level=0,.array_size=-1}; break;
    case TK_VOID:  ty = (_TY){.base=TY_VOID, .ptr_level=0,.array_size=-1}; break;
    case TK_FLOAT: ty = (_TY){.base=TY_FLOAT,.ptr_level=0,.array_size=-1}; break;
    case TK_LONG:  ty = (_TY){.base=TY_LONG, .ptr_level=0,.array_size=-1}; break;
    case TK_SHORT: ty = (_TY){.base=TY_SHORT,.ptr_level=0,.array_size=-1}; break;
    default:
      perror_expected(p->lx, "type keyword", _TN[p->cur.kind]);
      ty = (_TY){TY_INT,0,-1}; /* unreachable */
  }
  pnext(p);
  while (p->cur.kind == TK_STAR) { ty.ptr_level++; pnext(p); }
  return ty;
}

static _STN *pstmt(_P *p);
static _STN *pblock(_P *p) {
  pexpect(p, TK_LBRACE);
  pnext(p);

  _STN *head = NULL;
  _STN **cur = &head;

  while (p->cur.kind != TK_RBRACE && p->cur.kind != TK_EOF) {
    _STN *stmt = pstmt(p);
    *cur = stmt;
    cur = &stmt->n;
  }

  pexpect(p, TK_RBRACE);
  pnext(p);

  return st_block(head);
}
static _EX *pexpr(_P *p);
static _EX *pterm(_P *p);
static _EX *punary(_P *p);
static _EX *pfact(_P *p);
static _EX *pparse_charlit(_P *p);


static _EX *pmul(_P *p);
static _EX *padd(_P *p);
static _EX *pshift(_P *p);
static _EX *pbitand(_P *p);
static _EX *pbitxor(_P *p);
static _EX *pbitor(_P *p);
static _EX *prel(_P *p);
static _EX *peq(_P *p);
static _EX *plogand(_P *p);
static _EX *plogor(_P *p);

static _STN *passign_or_expr_stmt(_P *p) {
  _EX *lhs = pexpr(p);
  if (p->cur.kind == TK_ASSIGN) {
    if (!(lhs->kind == EX_VAR || lhs->kind == EX_DEREF || lhs->kind == EX_INDEX)) {
      fprintf(stderr, "[PARSER] Error at line %d, column %d: invalid assignment target in expression context\n", p->lx->line, p->lx->col);
      exit(1);
    }
    pnext(p);
    _EX *rhs = pexpr(p);
    return st_assign(lhs, rhs);
  }

  _TK compound_op = TK_INVALID;
  if      (p->cur.kind == TK_PLUS_EQ)  compound_op = TK_PLUS;
  else if (p->cur.kind == TK_MINUS_EQ) compound_op = TK_MINUS;
  else if (p->cur.kind == TK_STAR_EQ)  compound_op = TK_STAR;
  else if (p->cur.kind == TK_SLASH_EQ) compound_op = TK_SLASH;
  if (compound_op != TK_INVALID) {
    if (!(lhs->kind == EX_VAR || lhs->kind == EX_DEREF || lhs->kind == EX_INDEX)) {
      fprintf(stderr, "[PARSER] Error at line %d, column %d: invalid compound-assignment target\n", p->lx->line, p->lx->col);
      exit(1);
    }
    pnext(p);
    _EX *rhs = pexpr(p);
    _EX *combined = ex_binop(lhs, compound_op, rhs);
    return st_assign(lhs, combined);
  }
  return st_expr(lhs);
}

static _EX *ppostfix_from_expr(_P *p, _EX *e) {
  for (;;) {
    if (p->cur.kind == TK_LBRACKET) {
      pnext(p);
      _EX *index = pexpr(p);
      pexpect(p, TK_RBRACKET);
      pnext(p);
      e = ex_index(e, index);
    } else if (p->cur.kind == TK_INC || p->cur.kind == TK_DEC) {
      _TK op = p->cur.kind;
      pnext(p);
      _EX *one = ex_number(1);
      e = ex_binop(e, op, one);
    } else {
      break;
    }
  }
  return e;
}

static _EX *ppostfix(_P *p) {
  _EX *e = pfact(p);
  return ppostfix_from_expr(p, e);
}


static _EX *pfact(_P *p) {
  if (p->cur.kind == TK_NUMBER) {
    _EX *n = ex_number(p->cur.val);
    pnext(p);
    return n;

  } else if (p->cur.kind == TK_IDENT) {
    char *name = strdup(p->cur.lxem);
    if (!name) {
      fprintf(stderr, "[PARSER] Error: strdup failed for identifier\n");
      exit(1);
    }
    pnext(p);

    if (p->cur.kind == TK_LPAREN) {

      pnext(p);

      _EX **args = NULL;
      int argc = 0;

      if (p->cur.kind != TK_RPAREN) {
        do {
      args = realloc(args, sizeof(_EX *) * (argc + 1));
      if (!args) {
        fprintf(stderr, "[PARSER] Error at line %d, column %d: out of memory while parsing function arguments\n", p->lx->line, p->lx->col);
        exit(1);
      }
          args[argc++] = pexpr(p);

          if (p->cur.kind == TK_COMMA) {
            pnext(p);
          } else {
            break;
          }
        } while (1);
      }

      pexpect(p, TK_RPAREN);
      pnext(p);

      return ex_call(name, args, argc);
    }

    _EX *var_expr = ex_var(name);
    return ppostfix_from_expr(p, var_expr);

  } else if (p->cur.kind == TK_LPAREN) {
    pnext(p);

    if (p->cur.kind == TK_INT   || p->cur.kind == TK_CHAR  ||
        p->cur.kind == TK_SHORT || p->cur.kind == TK_LONG  ||
        p->cur.kind == TK_VOID  || p->cur.kind == TK_FLOAT) {
      _TY to = pparse_type(p);
      pexpect(p, TK_RPAREN);
      pnext(p);
      _EX *sub = punary(p);
      return ppostfix_from_expr(p, ex_cast(to, sub));
    }
    _EX *n = pexpr(p);
    pexpect(p, TK_RPAREN);
    pnext(p);
    return ppostfix_from_expr(p, n);

  } else if (p->cur.kind == TK_STRING) {
    char *str = strdup(p->cur.lxem);
    if (!str) {
      fprintf(stderr, "[PARSER] Error: strdup failed for string literal\n");
      exit(1);
    }
    pnext(p);
    return ex_string(str);

  } else if (p->cur.kind == TK_CHARLIT) {
    return pparse_charlit(p);

  } else {
    perror_unexpected(p->lx, "factor", _TN[p->cur.kind]);
  }
}

static _EX *pmul(_P *p) {
  _EX *n = punary(p);
  while (p->cur.kind == TK_STAR || p->cur.kind == TK_SLASH || p->cur.kind == TK_PERCENT) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = punary(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *padd(_P *p) {
  _EX *n = pmul(p);
  while (p->cur.kind == TK_PLUS || p->cur.kind == TK_MINUS) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = pmul(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *pshift(_P *p) {
  _EX *n = padd(p);
  while (p->cur.kind == TK_SHL || p->cur.kind == TK_SHR) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = padd(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *pbitand(_P *p) {
  _EX *n = peq(p);
  while (p->cur.kind == TK_AMP) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = peq(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *pbitxor(_P *p) {
  _EX *n = pbitand(p);
  while (p->cur.kind == TK_CARET) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = pbitand(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *pbitor(_P *p) {
  _EX *n = pbitxor(p);
  while (p->cur.kind == TK_BAR) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = pbitxor(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *prel(_P *p) {
  _EX *n = pshift(p);
  while (p->cur.kind == TK_LT || p->cur.kind == TK_LE || p->cur.kind == TK_GT || p->cur.kind == TK_GE) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = pshift(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *peq(_P *p) {
  _EX *n = prel(p);
  while (p->cur.kind == TK_EQ || p->cur.kind == TK_NE) {
    _TK op = p->cur.kind;
    pnext(p);
    _EX *r = prel(p);
    n = ex_binop(n, op, r);
  }
  return n;
}

static _EX *plogand(_P *p) {
  _EX *n = pbitor(p);
  while (p->cur.kind == TK_AND) {
    pnext(p);
    _EX *r = pbitor(p);
    n = ex_binop(n, TK_AND, r);
  }
  return n;
}

static _EX *plogor(_P *p) {
  _EX *n = plogand(p);
  while (p->cur.kind == TK_OR) {
    pnext(p);
    _EX *r = plogand(p);
    n = ex_binop(n, TK_OR, r);
  }
  return n;
}

static _EX *pexpr(_P *p) {
  _EX *n = plogor(p);
  if (p->cur.kind == TK_QUESTION) {
    pnext(p); /* consume '?' */
    _EX *then_e = pexpr(p);
    if (p->cur.kind != TK_COLON) {
      fprintf(stderr, "[PARSER] Error at line %d, column %d: expected ':' in ternary\n",
              p->lx->line, p->lx->col);
      exit(1);
    }
    pnext(p); /* consume ':' */
    _EX *else_e = pexpr(p);
    return ex_ternary(n, then_e, else_e);
  }
  return n;
}

static _EX *punary(_P *p) {
  if (p->cur.kind == TK_AMP) {
    pnext(p);
    _EX *sub = punary(p);
    NEW_EX(EX_ADDR);
    e->addr.expr = sub;
    return e;
  }
  if (p->cur.kind == TK_STAR) {
    pnext(p);
    _EX *sub = punary(p);
    NEW_EX(EX_DEREF);
    e->deref.expr = sub;
    return e;
  }
  if (p->cur.kind == TK_BANG) {
    pnext(p);
    _EX *sub = punary(p);
    _EX *zero = ex_number(0);
    return ex_binop(sub, TK_EQ, zero);
  }
  if (p->cur.kind == TK_MINUS) {
    pnext(p);
    _EX *sub = punary(p);
    return ex_binop(ex_number(0), TK_MINUS, sub);
  }
  if (p->cur.kind == TK_INC || p->cur.kind == TK_DEC) {
    _TK op = (p->cur.kind == TK_INC) ? TK_INC : TK_DEC;
    pnext(p);
    _EX *sub = punary(p);
    return ex_binop(sub, op, ex_number(-1));
  }
  if (p->cur.kind == TK_SIZEOF) {
    pnext(p); /* consume sizeof */
    pexpect(p, TK_LPAREN); pnext(p);
    int sz = 0;
    if (p->cur.kind == TK_INT || p->cur.kind == TK_CHAR ||
        p->cur.kind == TK_SHORT || p->cur.kind == TK_LONG ||
        p->cur.kind == TK_VOID || p->cur.kind == TK_FLOAT) {
      _TY ty = pparse_type(p);
      if (ty.ptr_level > 0) sz = 8;
      else {
        switch (ty.base) {
          case TY_CHAR:  sz = 1; break;
          case TY_SHORT: sz = 2; break;
          case TY_INT:   sz = 4; break;
          case TY_LONG:  sz = 8; break;
          default:       sz = 4; break;
        }
      }
      if (ty.array_size > 0) sz *= ty.array_size;
    } else {
      /* sizeof(expr) — resolved at JIT time via __sizeof__ built-in */
      _EX *inner = pexpr(p);
      pexpect(p, TK_RPAREN); pnext(p);
      _EX **args = (_EX **)malloc(sizeof(_EX *));
      if (!args) { fprintf(stderr, "[PARSER] OOM in sizeof\n"); exit(1); }
      args[0] = inner;
      return ex_call(strdup("__sizeof__"), args, 1);
    }
    pexpect(p, TK_RPAREN); pnext(p);
    return ex_number(sz);
  }
  return ppostfix(p);
}
static _EX *pparse_charlit(_P *p) {
  int value = p->cur.val;
  pnext(p);
  _EX *e = (_EX *)calloc(1, sizeof(_EX));
  if (!e) { fprintf(stderr, "[PARSER] Error: calloc failed in pparse_charlit\n"); exit(1); }
  e->kind  = EX_NUMBER;
  e->value = value;
  return e;
}

static char parse_char_literal(_P *p) {
  char c = (char)p->cur.val;
  pnext(p);
  return c;
}
static _EX *ex_charlit(char c) {
  _EX *e = (_EX *)calloc(1, sizeof(_EX));
  if (!e) { fprintf(stderr, "[PARSER] Error: calloc failed in ex_charlit\n"); exit(1); }
  e->kind = EX_NUMBER;
  e->value = (unsigned char)c;
  return e;
}

static _STN *pstmt(_P *p) {
  switch (p->cur.kind) {
  case TK_IF: {
    pnext(p);
    pexpect(p, TK_LPAREN); pnext(p);
    _EX *cond = pexpr(p);
    pexpect(p, TK_RPAREN); pnext(p);
    _STN *thenb = pstmt(p);
    _STN *elseb = NULL;
    if (p->cur.kind == TK_ELSE) { pnext(p); elseb = pstmt(p); }
    return st_if(cond, thenb, elseb);
  }
  case TK_WHILE: {
    pnext(p);
    pexpect(p, TK_LPAREN); pnext(p);
    _EX *cond = pexpr(p);
    pexpect(p, TK_RPAREN); pnext(p);
    _STN *body = pstmt(p);
    return st_while(cond, body);
  }
  case TK_DO: {
    pnext(p); /* consume 'do' */
    _STN *body = pstmt(p);
    if (p->cur.kind != TK_WHILE) {
      fprintf(stderr, "[PARSER] Error at line %d, column %d: expected 'while' after do body\n",
              p->lx->line, p->lx->col);
      exit(1);
    }
    pnext(p); /* consume 'while' */
    pexpect(p, TK_LPAREN); pnext(p);
    _EX *cond = pexpr(p);
    pexpect(p, TK_RPAREN); pnext(p);
    pexpect(p, TK_SEMI);   pnext(p);
    return st_dowhile(body, cond);
  }
  case TK_BREAK: {
    pnext(p); /* consume 'break' */
    pexpect(p, TK_SEMI); pnext(p);
    return st_break();
  }
  case TK_CONTINUE: {
    pnext(p); /* consume 'continue' */
    pexpect(p, TK_SEMI); pnext(p);
    return st_continue();
  }
  case TK_FOR: {
    pnext(p);
    pexpect(p, TK_LPAREN); pnext(p);
    _STN *init = NULL; _EX *cond = NULL; _STN *step = NULL;
    if (p->cur.kind != TK_SEMI) {
      init = pstmt(p);
    } else { pnext(p); }
    if (p->cur.kind != TK_SEMI) {
      cond = pexpr(p);
    }
    pexpect(p, TK_SEMI); pnext(p);
    if (p->cur.kind != TK_RPAREN) {
      step = passign_or_expr_stmt(p);
    }
    pexpect(p, TK_RPAREN); pnext(p);
    _STN *body = pstmt(p);
    return st_for(init, cond, step, body);
  }
  case TK_VOID:
  case TK_FLOAT:
  case TK_LONG:
  case TK_SHORT:
  case TK_INT:
  case TK_CHAR: {
    _TY vtype = pparse_type(p);

    if (p->cur.kind != TK_IDENT) {
      perror_expected(p->lx, "variable name after type", _TN[p->cur.kind]);
    }
    char *name = strdup(p->cur.lxem);
    if (!name) {
      fprintf(stderr, "[PARSER] Error: strdup failed for variable name\n");
      exit(1);
    }
    pnext(p);
    
    if (p->cur.kind == TK_LBRACKET) {
      pnext(p);
      if (p->cur.kind == TK_NUMBER) {
        vtype.array_size = p->cur.val;
        pnext(p);
      } else {
        vtype.array_size = 0; // unknown size []
      }
      pexpect(p, TK_RBRACKET);
      pnext(p);
    }

    _EX *init = NULL;
    if (p->cur.kind == TK_ASSIGN) {
      pnext(p);

      if (p->cur.kind == TK_LBRACE) {
        pnext(p);
        _EX **elems = NULL;
        int  nelems = 0;
        while (p->cur.kind != TK_RBRACE && p->cur.kind != TK_EOF) {
          elems = (_EX **)realloc(elems, sizeof(_EX *) * (nelems + 1));
          if (!elems) { fprintf(stderr, "[PARSER] OOM in initializer list\n"); exit(1); }
          elems[nelems++] = pexpr(p);
          if (p->cur.kind == TK_COMMA) pnext(p);
        }
        pexpect(p, TK_RBRACE); pnext(p);
        init = ex_call(strdup("__initlist__"), elems, nelems);
      } else if (vtype.ptr_level == 0 && vtype.base == TY_CHAR && p->cur.kind == TK_CHARLIT) {
        init = pparse_charlit(p);
      } else {
        init = pexpr(p);
      }
    }

    pexpect(p, TK_SEMI);
    pnext(p);

    _STN *decl = st_var_decl(name, init);
    decl->var_decl.type = vtype;
    return decl;
  }

  case TK_IDENT: {
    _EX *lhs_or_call = pfact(p); /* starts from ident path */
    if (p->cur.kind == TK_ASSIGN) {
      pnext(p);
      _EX *rhs = pexpr(p);
      pexpect(p, TK_SEMI); pnext(p);
      return st_assign(lhs_or_call, rhs);
    }
    _TK cop = TK_INVALID;
    if      (p->cur.kind == TK_PLUS_EQ)  cop = TK_PLUS;
    else if (p->cur.kind == TK_MINUS_EQ) cop = TK_MINUS;
    else if (p->cur.kind == TK_STAR_EQ)  cop = TK_STAR;
    else if (p->cur.kind == TK_SLASH_EQ) cop = TK_SLASH;
    if (cop != TK_INVALID) {
      pnext(p);
      _EX *rhs = pexpr(p);
      pexpect(p, TK_SEMI); pnext(p);
      return st_assign(lhs_or_call, ex_binop(lhs_or_call, cop, rhs));
    }
    pexpect(p, TK_SEMI); pnext(p);
    return st_expr(lhs_or_call);
  }
  case TK_RETURN: {
    pnext(p);
    _EX *expr = pexpr(p);
    pexpect(p, TK_SEMI);
    pnext(p); /* consume ';' */

    return st_return(expr);
  }
  case TK_LBRACE: {
    return pblock(p);
  }
  default: {
    _EX *lhs = pexpr(p);
    if (p->cur.kind == TK_ASSIGN) {
      if (!(lhs->kind == EX_VAR || lhs->kind == EX_DEREF || lhs->kind == EX_INDEX)) {
        fprintf(stderr, "[PARSER] Error at line %d, column %d: invalid assignment target - only variables, dereferenced expressions, and array indexing allowed\n", p->lx->line, p->lx->col);
        exit(1);
      }
      pnext(p);
      _EX *rhs = pexpr(p);
      pexpect(p, TK_SEMI); pnext(p);
      return st_assign(lhs, rhs);
    }
    _TK dcop = TK_INVALID;
    if      (p->cur.kind == TK_PLUS_EQ)  dcop = TK_PLUS;
    else if (p->cur.kind == TK_MINUS_EQ) dcop = TK_MINUS;
    else if (p->cur.kind == TK_STAR_EQ)  dcop = TK_STAR;
    else if (p->cur.kind == TK_SLASH_EQ) dcop = TK_SLASH;
    if (dcop != TK_INVALID) {
      if (!(lhs->kind == EX_VAR || lhs->kind == EX_DEREF || lhs->kind == EX_INDEX)) {
        fprintf(stderr, "[PARSER] Error at line %d, column %d: invalid compound-assignment target\n", p->lx->line, p->lx->col);
        exit(1);
      }
      pnext(p);
      _EX *rhs = pexpr(p);
      pexpect(p, TK_SEMI); pnext(p);
      return st_assign(lhs, ex_binop(lhs, dcop, rhs));
    }
    pexpect(p, TK_SEMI);
    pnext(p);
    return st_expr(lhs);
  }
  }
}

static _FN *pfunc(_P *p) {
  if (!is_type_token(p->cur.kind)) {
    perror_expected(p->lx, "return type for function", _TN[p->cur.kind]);
  }
  _TY ret_type = pparse_type(p);

  if (p->cur.kind != TK_IDENT) {
    perror_expected(p->lx, "function name after return type", _TN[p->cur.kind]);
  }
  char *name = NULL;
  if (p->cur.lxem)
    name = strdup(p->cur.lxem);
  if (p->cur.lxem && !name) {
    fprintf(stderr, "[PARSER] Error: strdup failed for function name\n");
    exit(1);
  }
  pnext(p);

  pexpect(p, TK_LPAREN);
  pnext(p);

  char **params = NULL;
  _TY *params_types = NULL;
  int pac = 0;

  if (p->cur.kind != TK_RPAREN) {
    while (1) {
      if (!is_type_token(p->cur.kind)) {
        perror_expected(p->lx, "type in parameter list", _TN[p->cur.kind]);
      }
      _TY vtype = pparse_type(p);

      if (p->cur.kind != TK_IDENT) {
        perror_expected(p->lx, "identifier after type in parameter list", _TN[p->cur.kind]);
      }
      
      char *param_name = strdup(p->cur.lxem);
      if (!param_name) {
        fprintf(stderr, "[PARSER] Error: strdup failed for parameter name\n");
        exit(1);
      }
      pnext(p);
      if (p->cur.kind == TK_LBRACKET) {
        pnext(p);
        if (p->cur.kind == TK_NUMBER) {
          vtype.array_size = p->cur.val;
          pnext(p);
        } else {
          vtype.array_size = 0; // unknown size []
        }
        pexpect(p, TK_RBRACKET);
        pnext(p);
      }

      char **new_params = (char **)realloc(params, sizeof(char *) * (pac + 1));
      _TY *new_param_types = (_TY *)realloc(params_types, sizeof(_TY) * (pac + 1));
      if (!new_params || !new_param_types) {
        fprintf(stderr, "[PARSER] Error at line %d, column %d: out of memory while parsing function parameters\n", p->lx->line, p->lx->col);
        free(new_params);
        free(new_param_types);
        exit(1);
      }
      params = new_params;
      params_types = new_param_types;
      params[pac] = param_name;
      params_types[pac] = vtype;
      pac++;

      if (p->cur.kind == TK_COMMA) {
        pnext(p);
        continue;
      } else {
        break;
      }
    }
  }

  pexpect(p, TK_RPAREN);
  pnext(p);

  _STN *body = pblock(p);

  return fn_new(name, params, params_types, pac, body, ret_type);
}

static _FN *parse_program(_LX *lx) {
  _P pstate = {.lx = lx, .cur = lxnext(lx)};

  _FN *head = NULL;
  _FN **cur = &head;

  while (pstate.cur.kind != TK_EOF) {
    if (!is_type_token(pstate.cur.kind)) {
      perror_unexpected(pstate.lx, "top-level declaration", _TN[pstate.cur.kind]);
    }

    /* Peek ahead: type ident ';'/'='/'[' → global var; type ident '(' → function */
    _TY gtype = pparse_type(&pstate);

    if (pstate.cur.kind != TK_IDENT) {
      perror_expected(pstate.lx, "identifier after type", _TN[pstate.cur.kind]);
    }
    char *gname = strdup(pstate.cur.lxem);
    if (!gname) { fprintf(stderr, "[PARSER] OOM\n"); exit(1); }
    pnext(&pstate); /* consume ident */

    if (pstate.cur.kind == TK_LBRACKET) {
      pnext(&pstate);
      if (pstate.cur.kind == TK_NUMBER) {
        gtype.array_size = pstate.cur.val; pnext(&pstate);
      } else {
        gtype.array_size = 0;
      }
      pexpect(&pstate, TK_RBRACKET); pnext(&pstate);
    }

    if (pstate.cur.kind == TK_LPAREN) {
      pnext(&pstate); /* consume '(' */

      char **params = NULL;
      _TY *param_types = NULL;
      int pac = 0;

      if (pstate.cur.kind != TK_RPAREN) {
        do {
          if (!is_type_token(pstate.cur.kind)) break;
          _TY ptype = pparse_type(&pstate);
          char *pname = NULL;
          if (pstate.cur.kind == TK_IDENT) {
            pname = strdup(pstate.cur.lxem);
            if (!pname) { fprintf(stderr, "[PARSER] OOM\n"); exit(1); }
            pnext(&pstate);
          } else {
            pname = strdup("_anon");
          }
          params      = realloc(params,      sizeof(char*) * (pac+1));
          param_types = realloc(param_types, sizeof(_TY)   * (pac+1));
          if (!params || !param_types) { fprintf(stderr, "[PARSER] OOM\n"); exit(1); }
          params[pac]      = pname;
          param_types[pac] = ptype;
          pac++;
          if (pstate.cur.kind == TK_COMMA) pnext(&pstate); else break;
        } while (1);
      }
      pexpect(&pstate, TK_RPAREN); pnext(&pstate);

      _STN *body = pblock(&pstate);

      _FN *f = fn_new(gname, params, param_types, pac, body, gtype);
      *cur = f;
      cur = &f->n;
    } else {
      _EX *init = NULL;
      if (pstate.cur.kind == TK_ASSIGN) {
        pnext(&pstate);
        if (pstate.cur.kind == TK_LBRACE) {
          /* initializer list for global array */
          pnext(&pstate);
          _EX **elems = NULL; int nelems = 0;
          while (pstate.cur.kind != TK_RBRACE && pstate.cur.kind != TK_EOF) {
            elems = realloc(elems, sizeof(_EX*) * (nelems+1));
            if (!elems) { fprintf(stderr, "[PARSER] OOM\n"); exit(1); }
            elems[nelems++] = pexpr(&pstate);
            if (pstate.cur.kind == TK_COMMA) pnext(&pstate);
          }
          pexpect(&pstate, TK_RBRACE); pnext(&pstate);
          init = ex_call(strdup("__initlist__"), elems, nelems);
        } else {
          init = pexpr(&pstate);
        }
      }
      pexpect(&pstate, TK_SEMI); pnext(&pstate);


      char *gfunc_name = malloc(strlen(gname) + 12);
      if (!gfunc_name) { fprintf(stderr, "[PARSER] OOM\n"); exit(1); }
      sprintf(gfunc_name, "__global_%s__", gname);

      _STN *gdecl = st_global(gname, gtype, init);  /* gdecl takes ownership of gname */
      _FN  *gf    = fn_new(gfunc_name, NULL, NULL, 0, gdecl,
                           (_TY){TY_VOID,0,-1});
      *cur = gf;
      cur  = &gf->n;
    }
  }

  if (pstate.cur.lxem) {
    free(pstate.cur.lxem);
    pstate.cur.lxem = NULL;
  }

  return head;
}

#endif /* INCLUDE_parser */