1 files changed, 42 insertions, 54 deletions

diff --git a/shell/math.h b/shell/math.h
index 96088b4d2..2d305eb12 100644
--- a/shell/math.h
+++ b/shell/math.h
@@ -9,67 +9,53 @@
 
 /* The math library has just one function:
  *
- *      arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t *hooks);
+ * arith_t arith(arith_state_t *state, const char *expr);
  *
- *      The first argument is the math string to parse.  All normal expansions must
- *      be done already.  i.e. no dollar symbols should be present.
+ * The expr argument is the math string to parse.  All normal expansions must
+ * be done already.  i.e. no dollar symbols should be present.
  *
- *      The second argument is a semi-detailed error description in case something
- *      goes wrong in the parsing steps.  Currently, those values are (for
- *      compatibility, you should assume all negative values are errors):
- *               0 - no errors (yay!)
- *              -1 - unspecified problem
- *              -2 - divide by zero
- *              -3 - exponent less than 0
- *              -5 - expression recursion loop detected
+ * The state argument is a pointer to a struct of hooks for your shell (see below),
+ * and an error message string (NULL if no error).
  *
- *      The third argument is a struct pointer of hooks for your shell (see below).
- *
- *      The function returns the answer to the expression.  So if you called it
- *      with the expression:
- *              "1 + 2 + 3"
- *      You would obviously get back 6.
+ * The function returns the answer to the expression.  So if you called it
+ * with the expression:
+ * "1 + 2 + 3"
+ * you would obviously get back 6.
  */
 
 /* To add support to a shell, you need to implement three functions:
  *
- *      lookupvar() - look up and return the value of a variable
+ * lookupvar() - look up and return the value of a variable
  *
- *              If the shell does:
- *                      foo=123
- *              Then the code:
- *                      const char *val = lookupvar("foo");
- *              Will result in val pointing to "123"
+ *      If the shell does:
+ *              foo=123
+ *      Then the code:
+ *              const char *val = lookupvar("foo");
+ *      will result in val pointing to "123"
  *
- *      setvar() - set a variable to some value
+ * setvar() - set a variable to some value
  *
- *              If the arithmetic expansion does something like:
- *                      $(( i = 1))
- *              Then the math code will make a call like so:
- *                      setvar("i", "1", 0);
- *              The storage for the first two parameters are not allocated, so your
- *              shell implementation will most likely need to strdup() them to save.
+ *      If the arithmetic expansion does something like:
+ *              $(( i = 1))
+ *      then the math code will make a call like so:
+ *              setvar("i", "1", 0);
+ *      The storage for the first two parameters are not allocated, so your
+ *      shell implementation will most likely need to strdup() them to save.
  *
- *      endofname() - return the end of a variable name from input
+ * endofname() - return the end of a variable name from input
  *
- *              The arithmetic code does not know about variable naming conventions.
- *              So when it is given an experession, it knows something is not numeric,
- *              but it is up to the shell to dictate what is a valid identifiers.
- *              So when it encounters something like:
- *                      $(( some_var + 123 ))
- *              It will make a call like so:
- *                      end = endofname("some_var + 123");
- *              So the shell needs to scan the input string and return a pointer to the
- *              first non-identifier string.  In this case, it should return the input
- *              pointer with an offset pointing to the first space.  The typical
- *              implementation will return the offset of first char that does not match
- *              the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]*
- */
-
-/* To make your life easier when dealing with optional 64bit math support,
- * rather than assume that the type is "signed long" and you can always
- * use "%ld" to scan/print the value, use the arith_t helper defines.  See
- * below for the exact things that are available.
+ *      The arithmetic code does not know about variable naming conventions.
+ *      So when it is given an experession, it knows something is not numeric,
+ *      but it is up to the shell to dictate what is a valid identifiers.
+ *      So when it encounters something like:
+ *              $(( some_var + 123 ))
+ *      It will make a call like so:
+ *              end = endofname("some_var + 123");
+ *      So the shell needs to scan the input string and return a pointer to the
+ *      first non-identifier string.  In this case, it should return the input
+ *      pointer with an offset pointing to the first space.  The typical
+ *      implementation will return the offset of first char that does not match
+ *      the regex (in C locale): ^[a-zA-Z_][a-zA-Z_0-9]*
  */
 
 #ifndef SHELL_MATH_H
@@ -79,11 +65,11 @@ PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 
 #if ENABLE_SH_MATH_SUPPORT_64
 typedef long long arith_t;
-#define arith_t_fmt "%lld"
+#define ARITH_FMT "%lld"
 #define strto_arith_t strtoull
 #else
 typedef long arith_t;
-#define arith_t_fmt "%ld"
+#define ARITH_FMT "%ld"
 #define strto_arith_t strtoul
 #endif
 
@@ -96,13 +82,15 @@ typedef const char* FAST_FUNC (*arith_var_lookup_t)(const char *name);
 typedef void        FAST_FUNC (*arith_var_set_t)(const char *name, const char *val);
 //typedef const char* FAST_FUNC (*arith_var_endofname_t)(const char *name);
 
-typedef struct arith_eval_hooks {
+typedef struct arith_state_t {
+        const char           *errmsg;
         arith_var_lookup_t    lookupvar;
         arith_var_set_t       setvar;
 //      arith_var_endofname_t endofname;
-} arith_eval_hooks_t;
+        void                 *list_of_recursed_names;
+} arith_state_t;
 
-arith_t arith(const char *expr, int *perrcode, arith_eval_hooks_t*);
+arith_t FAST_FUNC arith(arith_state_t *state, const char *expr);
 
 POP_SAVED_FUNCTION_VISIBILITY