* eval.c (eval_init): New intrinsic num-str registered.

* filter.c (tonumber_k, tointeger_k, tofloat_k, hextoint_k):
New keyword variables.
(filter_init): New variables initialized; new filters registered.

* filter.h (tonumber_k, tointeger_k, tofloat_k, hextoint_k):
Declared.

* lib.c (num_str): New function.

* lib.h (num_str): Declared.

* txr.1: New filters documented.

7 files changed, 71 insertions, 5 deletions

diff --git a/ChangeLog b/ChangeLog
index c57dd97d..3c3010ec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,22 @@
 2012-03-26  Kaz Kylheku  <kaz@kylheku.com>
 
+	* eval.c (eval_init): New intrinsic num-str registered.
+
+	* filter.c (tonumber_k, tointeger_k, tofloat_k, hextoint_k):
+	New keyword variables.
+	(filter_init): New variables initialized; new filters registered.
+
+	* filter.h (tonumber_k, tointeger_k, tofloat_k, hextoint_k):
+	Declared.
+
+	* lib.c (num_str): New function.
+
+	* lib.h (num_str): Declared.
+
+	* txr.1: New filters documented.
+
+2012-03-26  Kaz Kylheku  <kaz@kylheku.com>
+
 	* arith.c (to_float): Fix unterminated argument list in throwf.
 
 	* lib.c (funcall): Likewise.
diff --git a/eval.c b/eval.c
index 644998f0..4a028ca4 100644
--- a/eval.c
+++ b/eval.c
@@ -2302,6 +2302,7 @@ void eval_init(void)
   reg_fun(intern(lit("string-lt"), user_package), func_n2(string_lt));
   reg_fun(intern(lit("int-str"), user_package), func_n2o(int_str, 1));
   reg_fun(intern(lit("flo-str"), user_package), func_n1(flo_str));
+  reg_fun(intern(lit("num-str"), user_package), func_n1(num_str));
   reg_fun(intern(lit("int-flo"), user_package), func_n1(int_flo));
   reg_fun(intern(lit("flo-int"), user_package), func_n1(flo_int));
   reg_fun(intern(lit("chrp"), user_package), func_n1(chrp));
diff --git a/filter.c b/filter.c
index 44e83936..3fc262a7 100644
--- a/filter.c
+++ b/filter.c
@@ -45,6 +45,7 @@ val filters;
 val filter_k, lfilt_k, rfilt_k, to_html_k, from_html_k;
 val upcase_k, downcase_k, fun_k;
 val topercent_k, frompercent_k, tourl_k, fromurl_k;
+val tonumber_k, tointeger_k, tofloat_k, hextoint_k;
 
 static val make_trie(void)
 {
@@ -669,6 +670,10 @@ void filter_init(void)
   frompercent_k = intern(lit("frompercent"), keyword_package);
   tourl_k = intern(lit("tourl"), keyword_package);
   fromurl_k = intern(lit("fromurl"), keyword_package);
+  tonumber_k = intern(lit("tonumber"), keyword_package);
+  tointeger_k = intern(lit("toinger"), keyword_package);
+  tofloat_k = intern(lit("tofloat"), keyword_package);
+  hextoint_k = intern(lit("hextoint"), keyword_package);
 
   sethash(filters, to_html_k, build_filter(to_html_table, t));
   {
@@ -683,4 +688,8 @@ void filter_init(void)
   sethash(filters, frompercent_k, curry_12_1(func_n2(url_decode), nil));
   sethash(filters, tourl_k, curry_12_1(func_n2(url_encode), t));
   sethash(filters, fromurl_k, curry_12_1(func_n2(url_decode), t));
+  sethash(filters, tonumber_k, func_n1(num_str));
+  sethash(filters, tointeger_k, curry_12_1(func_n2(int_str), nil));
+  sethash(filters, tofloat_k, func_n1(flo_str));
+  sethash(filters, hextoint_k, curry_12_1(func_n2(int_str), num_fast(16)));
 }
diff --git a/filter.h b/filter.h
index 806965c6..8c1c0df4 100644
--- a/filter.h
+++ b/filter.h
@@ -28,6 +28,7 @@ extern val filters;
 extern val filter_k, lfilt_k, rfilt_k, to_html_k, from_html_k;
 extern val upcase_k, downcase_k, fun_k;
 extern val topercent_k, frompercent_k, tourl_k, fromurl_k;
+extern val tonumber_k, tointeger_k, tofloat_k, hextoint_k;
 
 val trie_lookup_begin(val trie);
 val trie_value_at(val node);
diff --git a/lib.c b/lib.c
index a0872cf8..d738237e 100644
--- a/lib.c
+++ b/lib.c
@@ -1981,6 +1981,14 @@ val flo_str(val str)
   return flo(value);
 }
 
+val num_str(val str)
+{
+  const wchar_t *wcs = c_str(str);
+  if (wcspbrk(wcs, L".eE"))
+    return flo_str(str);
+  return int_str(str, nil);
+}
+
 val chrp(val chr)
 {
   return (is_chr(chr)) ? t : nil;
diff --git a/lib.h b/lib.h
index 5706aa6a..52695229 100644
--- a/lib.h
+++ b/lib.h
@@ -462,6 +462,7 @@ val trim_str(val str);
 val string_lt(val astr, val bstr);
 val int_str(val str, val base);
 val flo_str(val str);
+val num_str(val str);
 val int_flo(val f);
 val flo_int(val i);
 val chrp(val chr);
diff --git a/txr.1 b/txr.1
index 4441503e..50e063b8 100644
--- a/txr.1
+++ b/txr.1
@@ -3761,7 +3761,11 @@ implements named filters.  Built-in filters are named by keywords,
 given below. User-defined filters are possible, however.  See notes on the
 deffilter directive below.
 
-Built-in filters:
+Instead of a filter name, the syntax (fun NAME) can be used. This
+denotes that the function called NAME is to be used as a filter.
+This is discussed in the next section Function Filters below.
+
+Built-in filters named by keywords:
 
 .IP :to_html
 Filter text to HTML, representing special characters using HTML
@@ -3806,7 +3810,30 @@ Encode to URL encoding, which is like percent encoding except that
 a space maps to + rather than %20. The + character, being in the
 reserved set, encodes to %2B.
 
-Example: to escape HTML characters in all variable substitutions occuring in an
+.PP :tonumber
+Converts strings to numbers. Strings that contain a period, e or E are
+converted to floating point as if by the function flo-str. Otherwise
+they are converted to integer as if using int-str with a radix of 10.
+Non-numeric junk results in the object nil.
+
+.PP :tointeger
+Converts strings to integers as if using int-str with a radix of 10.
+Non-numeric junk results in the object nil.
+
+.PP :tofloat
+Converts strings to floating-point values as if using the function flo-str.
+Non-numeric junk results in the object nil.
+
+.PP :hextoint
+Converts strings to integers as if using int-str with a radix of 16.
+Non-numeric junk results in the object nil.
+
+.PP
+
+.TP
+Examples
+
+To escape HTML characters in all variable substitutions occuring in an
 output clause, specify :filter :to_html in the directive:
 
   @(output :filter :to_html)
@@ -3833,9 +3860,11 @@ because '&quot;' will turn to '&QUOT;' which no longer be recognized
 by the :from_html filter, because the entity names in HTML codes
 are case-sensitive.
 
-Instead of a filter name, the syntax (fun NAME) can be used. This
-denotes that the function called NAME is to be used as a filter.
-This is discussed in the next section Function Filters below.
+Capture some numeric variables and convert to numbers:
+
+  @date @time @temperature @pressure
+  @(filter :tofloat temperature pressure)
+  @;; temperature and pressure can now be used in calculations
 
 .SS Function Filters