Ruby -w

ruby-talk
1

Hello,

What does ‘ruby -w’ do? Could someone give me an example of the helpful
warnings that it might give?

I know of one warning that it does not give (compared to perl):

$ ruby -we ‘var = “hi”’
$
$ perl -we '$var = “hi”'
Name “main::var” used only once: possible typo at -e line 1.
$

Thanks,
Daniel.

2

Hi,

···

At Tue, 26 Nov 2002 04:23:56 +0900, Daniel Carrera wrote:

I know of one warning that it does not give (compared to perl):

$ ruby -we ‘var = “hi”’
$
$ perl -we ‘$var = “hi”’
Name “main::var” used only once: possible typo at -e line 1.
$

What about this patch?

$ ./i686-linux/miniruby -we ‘var = “hi”’
-e:1: warning: `var’ is assigned but not used

Index: eval.c

RCS file: /cvs/ruby/src/ruby/eval.c,v
retrieving revision 1.355
diff -u -2 -p -r1.355 eval.c
— eval.c 22 Nov 2002 09:32:50 -0000 1.355
+++ eval.c 26 Nov 2002 00:17:18 -0000
@@ -742,4 +742,12 @@ dvar_asgn_curr(id, value)
}

+void
+rb_dvar_asgn(id, value)

  • ID id;
  • VALUE value;
    +{
  • dvar_asgn(id, value, 0);
    +}

VALUE *
rb_svar(cnt)
Index: parse.y

RCS file: /cvs/ruby/src/ruby/parse.y,v
retrieving revision 1.229
diff -u -2 -p -r1.229 parse.y
— parse.y 17 Nov 2002 14:01:57 -0000 1.229
+++ parse.y 26 Nov 2002 00:19:57 -0000
@@ -2368,4 +2368,14 @@ int ruby__end__seen;
static VALUE ruby_debug_lines;

+static struct local_vars {

  • ID *tbl;
  • int nofree;
  • int cnt;
  • int dlev;
  • struct RVarmap* dyna_vars;
  • struct local_vars *prev;
  • int *used;
    +} *lvtbl;

static NODE*
yycompile(f, line)
@@ -4586,6 +4596,15 @@ gettable(id)
}
else if (is_local_id(id)) {

  • if (dyna_in_block() && rb_dvar_defined(id)) return NEW_DVAR(id);
  • if (local_id(id)) return NEW_LVAR(id);
  • int n;
  • if (dyna_in_block() && rb_dvar_defined(id)) {
  •   if (ruby_verbose && !ruby_in_eval) rb_dvar_asgn(id, Qnil);

  •   return NEW_DVAR(id);
  • }
  • if (n = local_id(id)) {
  •   if (lvtbl->used) {

  •   lvtbl->used[n-2] = 0;

  •   }

  •   return NEW_LVAR(id);
  • }
    /* method call without arguments */
    #if 0
    @@ -4647,5 +4666,5 @@ assignable(id, val)
    }
    else{
  •   rb_dvar_push(id, Qnil);

  •   rb_dvar_push(id, INT2FIX(ruby_sourceline));
  return NEW_DASGN_CURR(id, val);
    }
    @@ -5212,13 +5231,4 @@ new_super(a)
    }

-static struct local_vars {

  • ID *tbl;
  • int nofree;
  • int cnt;
  • int dlev;
  • struct RVarmap* dyna_vars;
  • struct local_vars *prev;
    -} *lvtbl;

static void
local_push(top)
@@ -5234,4 +5244,5 @@ local_push(top)
local->dlev = 0;
local->dyna_vars = ruby_dyna_vars;

  • local->used = 0;
    lvtbl = local;
    if (!top) {
    @@ -5247,4 +5258,16 @@ local_pop()
    struct local_vars *local = lvtbl->prev;

  • if (lvtbl->used) {

  • int i, max, line = ruby_sourceline;

  • for (i = 0, max = lvtbl->cnt - 2; i < max; ++i) {

  •   if (lvtbl->used[i]) {

  •   ruby_sourceline = lvtbl->used[i];

  •   rb_warn("`%s' is assigned but not used",

  •   	rb_id2name(lvtbl->tbl[i+3]));

  •   }

  • }

  • ruby_sourceline = line;

  • free(lvtbl->used);

  • }
    if (lvtbl->tbl) {
    if (!lvtbl->nofree) free(lvtbl->tbl);
    @@ -5281,4 +5304,8 @@ local_append(id)

    lvtbl->tbl[lvtbl->cnt+1] = id;

  • if (ruby_verbose) {

  • REALLOC_N(lvtbl->used, int, lvtbl->cnt);

  • lvtbl->used[lvtbl->cnt-2] = ruby_sourceline;

  • }
    return lvtbl->cnt++;
    }
    @@ -5304,9 +5331,9 @@ local_id(id)
    int i, max;

  • if (lvtbl == 0) return Qfalse;
  • if (lvtbl == 0) return 0;
    for (i=3, max=lvtbl->cnt+1; i<max; i++) {
  • if (lvtbl->tbl[i] == id) return Qtrue;
  • if (lvtbl->tbl[i] == id) return i-1;
    }
  • return Qfalse;
  • return 0;
    }

@@ -5383,4 +5410,16 @@ dyna_pop(vars)
struct RVarmap* vars;
{

  • if (ruby_verbose) {
  • struct RVarmap* v = ruby_dyna_vars;
  • int line = ruby_sourceline;
  • while (v && v != vars) {
  •   if (v->id && !NIL_P(v->val)) {

  •   ruby_sourceline = FIX2INT(v->val);

  •   rb_warn("`%s' is assigned but not used",

  •   	rb_id2name(v->id));

  •   }

  •   v = v->next;
  • }
  • }
    lvtbl->dlev–;
    ruby_dyna_vars = vars;

–
Nobu Nakada