# String#inspect may raise Exception

**URL:** <https://www.ruby-forum.com/t/string-inspect-may-raise-exception/127678>\
**Category:** Development\
**Created:** [January 31, 2008, 10:55am UTC](https://www.ruby-forum.com/t/string-inspect-may-raise-exception/127678 "2008-01-31T10:55:31Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![NARUSES\_Yui](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/n/258eb7/32.png) [@NARUSES\_Yui](https://www.ruby-forum.com/u/NARUSES_Yui)\
**Post date:** [January 31, 2008, 10:55am UTC](https://www.ruby-forum.com/t/string-inspect-may-raise-exception/127678/1 "2008-01-31T10:55:31Z")

</div>

e$B@.@%$G$9!#e(B

> ["\x82\xa0".force\_encoding(“sjis”),  
> “\xa4\xa2”.force\_encoding(“euc-jp”),  
> “\xe3\x81\x82”.force\_encoding(“utf-8”)].inspect  
> ArgumentError: append incompatible encoding strings: Shift\_JIS and  
> EUC-JP

e$B$H$J$j$^$9!#e(B

e$B;W$&$K!“8=:\_e(B String#inspect e$B$O\<+J,\<+?H$Ne(B encoding  
e$B$HCf?H$N%P%$%HNs$rHf3Se(B  
e$B$7$Fe(B valid  
e$B$J$i$P%(%9%1!\<%W$7$J$$$H$$$&=hM}$r9T$C$F$$$^$9$,!”\<+J,\<+?H$Ne(B  
encoding e$B$G$J$/!“7k2L$H$J$kJ8;zNs$Ne(B encoding  
e$B$r4p=`$H$9$kI,MW$,$”$k$H;We(B  
e$B$o$l$^$9!#e(B

e$B$D$^$k$H$3$m!“e(Binspect e$B$,0z?t$Ke(B encoding  
e$B$r\<h$kI,MW$,$”$k$N$G$9$,!“e(B  
inspect e$B$O:F5"E\*$K8F$P$l$k$?$a!”%f!\<%6!\<%_%V%8%’%/%H$G$be(B  
inspect(enc) e$B$,e(B  
e$BDj5A$5$l$F$$$kI,MW$,$"$j!"7k2LE_$K$3$N%"%W%m!\<%A$O;v**eIT2DG=$G$9!#e(B**

e$B?7;EMMBP1~$Ne(B inspect e$B$,%9%l%C%I%m!\<%+%kJQ?t$K4|BT$9$ke(B  
encoding e$B$r%;%C%He(B  
e$B$9$k$H$$$&5;$b$J$-$K$7$b$"$i$:$G$9$,!“8=:\_$N%^%k%A%P%$%HJ8;zNs$r%(%9%1!\<e(B  
e$B%W$J$7$K=PNO$9$k$H$$$&;EMM$r$”$-$i$a$6$k$r$($J$$$h$&$K46$8$^$9!#e(B

e$B$J$\*!“e(BString#inspect e$B$K8B$C$F!“0z?t$H$7$Fe(B encoding  
e$B$r\<h$k!”$H$$$&$N$J$ie(B  
e$B$P!”$=$l$O$$$^$@2DG=$G$O$"$j$^$9!#e(B

— string.c (revision 15383)  
+++ string.c (local)  
@@ -3259,23 +3259,6 @@  
return str;  
}

-static void  
-str\_cat\_char(VALUE str, int c, rb\_encoding \*enc)  
-{

- char s[16];
- int n = rb\_enc\_codelen(c, enc);
- 
- rb\_enc\_mbcput(c, s, enc);
- rb\_enc\_str\_buf\_cat(str, s, n, enc);  
-}
- 

-static void  
-prefix\_escape(VALUE str, int c, rb\_encoding \*enc)  
-{

- str\_cat\_char(str, ‘\’, enc);
- str\_cat\_char(str, c, enc);  
-}
- 

/\*

- call-seq:
- str.inspect =\> string  
@@ -3291,81 +3274,65 @@  
VALUE  
rb\_str\_inspect(VALUE str)  
{

- rb\_encoding \*enc = STR\_ENC\_GET(str);  
char \*p, \*pend;
- VALUE result = rb\_str\_buf\_new2("");

- VALUE result = rb\_str\_buf\_new2(""");

- rb\_enc\_associate(result, enc);
- str\_cat\_char(result, ‘"’, enc);

- ENCODING\_CODERANGE\_SET(result, rb\_usascii\_encindex(),  
ENC\_CODERANGE\_7BIT);  
p = RSTRING\_PTR(str); pend = RSTRING\_END(str);  
while (p \< pend) {

- 

```
  int c;

```

- 

```
  int n;

```

- 

```
  int c = *p++;
  int cc;

```

- 

```
   n = rb_enc_precise_mbclen(p, pend, enc);

```

- 

```
   if (!MBCLEN_CHARFOUND_P(n)) {

```

- 

```
       p++;

```

- 

```
       n = 1;

```

- 

```
       goto escape_codepoint;

```

- 

```
   }

```

- 

```
   n = MBCLEN_CHARFOUND_LEN(n);

```

- 
- 

```
  c = rb_enc_codepoint(p, pend, enc);

```

- 

```
  n = rb_enc_codelen(c, enc);

```

- 
- 

```
  p += n;

```

- 

```
  if (c == '"'|| c == '\\' ||

```

- 

```
      (c == '#' &&

```

- 

```
  if (c == '#' &&
        p < pend &&

```

- 

```
        MBCLEN_CHARFOUND_P(rb_enc_precise_mbclen(p,pend,enc)) &&

```

- 

```
        (cc = rb_enc_codepoint(p,pend,enc),

```

- 

```
         (cc == '$' || cc == '@' || cc == '{')))) {

```

- 

```
      prefix_escape(result, c, enc);

```

- 

```
        (cc = *(p),

```

- 

```
         (cc == '$' || cc == '@' || cc == '{'))) {

```

- 

```
      rb_str_buf_cat2(result, "\\#");
  }

```

- 

```
   else if (c == '"') {

```

- 

```
      rb_str_buf_cat2(result, "\\\"");

```

- 

```
   }

```

- 

```
   else if (c == '\\') {

```

- 

```
      rb_str_buf_cat2(result, "\\\\");

```

- 

```
   }
  else if (c == '\n') {

```

- 

```
      prefix_escape(result, 'n', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\n");
  }
  else if (c == '\r') {

```

- 

```
      prefix_escape(result, 'r', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\r");
  }
  else if (c == '\t') {

```

- 

```
      prefix_escape(result, 't', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\t");
  }
  else if (c == '\f') {

```

- 

```
      prefix_escape(result, 'f', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\f");
  }
  else if (c == '\013') {

```

- 

```
      prefix_escape(result, 'v', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\v");
  }
  else if (c == '\010') {

```

- 

```
      prefix_escape(result, 'b', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\b");
  }
  else if (c == '\007') {

```

- 

```
      prefix_escape(result, 'a', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\a");
  }
  else if (c == 033) {

```

- 

```
      prefix_escape(result, 'e', enc);

```

- 

```
      rb_str_buf_cat2(result, "\\e");
  }

```

- 

```
  else if (rb_enc_isprint(c, enc)) {

```

- 

```
      rb_enc_str_buf_cat(result, p-n, n, enc);

```

- 

```
  }
  else {
      char buf[5];
      char *s;
       char *q;

    escape_codepoint:

```

- 

```
       for (q = p-n; q < p; q++) {

```

- 

```
       for (q = p-1; q < p; q++) {
           s = buf;
           sprintf(buf, "\\x%02X", *q & 0377);

```

- 

```
           while (*s) {

```

- 

```
               str_cat_char(result, *s++, enc);

```

- 

```
           }

```

- 

```
           rb_str_buf_cat2(result, s);
       }
  }

```

}

- str\_cat\_char(result, ‘"’, enc);

- rb\_str\_buf\_cat2(result, “”");