From 8f93c9dfc67de6759f713809d7faa37c5cb7a30c Mon Sep 17 00:00:00 2001
From: JeffBezanson <jeff.bezanson@gmail.com>
Date: Mon, 23 Mar 2009 19:49:08 +0000
Subject: [PATCH] adding string->number

---
 femtolisp/flisp.h  |  1 +
 femtolisp/read.c   |  2 +-
 femtolisp/string.c | 30 +++++++++++++++++++++++++-----
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/femtolisp/flisp.h b/femtolisp/flisp.h
index 19ccdd6..452f833 100644
--- a/femtolisp/flisp.h
+++ b/femtolisp/flisp.h
@@ -141,6 +141,7 @@ value_t compare(value_t a, value_t b);  // -1, 0, or 1
 value_t equal(value_t a, value_t b);    // T or nil
 int equal_lispvalue(value_t a, value_t b);
 uptrint_t hash_lispvalue(value_t a);
+int isnumtok_base(char *tok, value_t *pval, int base);
 
 /* safe casts */
 cons_t *tocons(value_t v, char *fname);
diff --git a/femtolisp/read.c b/femtolisp/read.c
index d13f6e2..cfeed3c 100644
--- a/femtolisp/read.c
+++ b/femtolisp/read.c
@@ -17,7 +17,7 @@ static int symchar(char c)
     return (!isspace(c) && !strchr(special, c));
 }
 
-static int isnumtok_base(char *tok, value_t *pval, int base)
+int isnumtok_base(char *tok, value_t *pval, int base)
 {
     char *end;
     int64_t i64;
diff --git a/femtolisp/string.c b/femtolisp/string.c
index 7f2edd1..2269c0f 100644
--- a/femtolisp/string.c
+++ b/femtolisp/string.c
@@ -290,6 +290,14 @@ value_t fl_string_dec(value_t *args, u_int32_t nargs)
     return size_wrap(i);
 }
 
+static ulong get_radix_arg(value_t arg, char *fname)
+{
+    ulong radix = toulong(arg, fname);
+    if (radix < 2 || radix > 36)
+        lerror(ArgError, "%s: invalid radix", fname);
+    return radix;
+}
+
 value_t fl_numbertostring(value_t *args, u_int32_t nargs)
 {
     if (nargs < 1 || nargs > 2)
@@ -306,11 +314,8 @@ value_t fl_numbertostring(value_t *args, u_int32_t nargs)
         neg = 1;
     }
     ulong radix = 10;
-    if (nargs == 2) {
-        radix = toulong(args[1], "number->string");
-        if (radix < 2 || radix > 36)
-            lerror(ArgError, "number->string: invalid radix");
-    }
+    if (nargs == 2)
+        radix = get_radix_arg(args[1], "number->string");
     char buf[128];
     char *str = uint2str(buf, sizeof(buf), num, radix);
     if (neg && str > &buf[0])
@@ -318,6 +323,20 @@ value_t fl_numbertostring(value_t *args, u_int32_t nargs)
     return string_from_cstr(str);
 }
 
+value_t fl_stringtonumber(value_t *args, uint32_t nargs)
+{
+    if (nargs < 1 || nargs > 2)
+        argcount("string->number", nargs, 2);
+    char *str = tostring(args[0], "string->number");
+    value_t n;
+    ulong radix = 0;
+    if (nargs == 2)
+        radix = get_radix_arg(args[1], "string->number");
+    if (!isnumtok_base(str, &n, (int)radix))
+        return FL_F;
+    return n;
+}
+
 static builtinspec_t stringfunc_info[] = {
     { "string", fl_string },
     { "string?", fl_stringp },
@@ -333,6 +352,7 @@ static builtinspec_t stringfunc_info[] = {
     { "string.decode", fl_string_decode },
 
     { "number->string", fl_numbertostring },
+    { "string->number", fl_stringtonumber },
 
     { NULL, NULL }
 };