1 files changed, 111 insertions, 0 deletions
diff --git a/src/hs_parse_args.c b/src/hs_parse_args.c
new file mode 100644
index 0000000..6fb8f31
--- /dev/null
+++ b/src/hs_parse_args.c
@@ -0,0 +1,111 @@
+#include "honeysuckle.h"
+
+static bool check_parse(lua_State *L, int index, struct hs_arg *expected)
+{
+   switch(expected->type) {
+   case HS_BOOL:
+      if (!lua_isboolean(L, index))
+	 return false;
+      *(expected->ptr.boolean) = lua_toboolean(L, index);
+      return true;
+
+   case HS_INT:
+      if (!lua_isnumber(L, index))
+	 return false;
+      *(expected->ptr.integer) = lua_tointeger(L, index);
+      return true;
+
+   case HS_NUM:
+      if (!lua_isnumber(L, index))
+	 return false;
+      *(expected->ptr.number) = lua_tonumber(L, index);
+      return true;
+
+   case HS_STR:
+      if (!lua_isstring(L, index))
+	 return false;
+      *(expected->ptr.string) = (char *) lua_tostring(L, index);
+      return true;
+
+   case HS_TBL:
+      if (!lua_istable(L, index))
+	 return false;
+      *(expected->ptr.stack_index) = index;
+      return true;
+
+   case HS_FUNC:
+      if (!lua_isfunction(L, index))
+	 return false;
+      *(expected->ptr.stack_index) = index;
+      return true;
+
+   case HS_CFUNC:
+      if (!lua_iscfunction(L, index))
+	 return false;
+      *(expected->ptr.function) = lua_tocfunction(L, index);
+      return true;
+
+   case HS_USER:
+      if (!lua_isuserdata(L, index))
+	 return false;
+      *(expected->ptr.userdata) = lua_touserdata(L, index);
+      return true;
+
+   case HS_LIGHT:
+      if (!lua_islightuserdata(L, index))
+	 return false;
+      *(expected->ptr.userdata) = lua_touserdata(L, index);
+      return true;
+
+   case HS_NIL:
+      if (!lua_isnil(L, index))
+	 return false;
+      *(expected->ptr.stack_index) = index;
+
+   case HS_ANY:
+      *(expected->ptr.stack_index) = index;
+      return true;
+
+   default:
+      return false;
+   }
+}
+
+
+static bool try_parse_args(lua_State *L, int n_args, struct hs_arg *arguments)
+{
+   int args_provided = lua_gettop(L);
+   if (args_provided != n_args)
+      return false;
+
+   for (int i=0; i<n_args; i++) {
+      bool success = check_parse(L, i+1, arguments + i);
+      if (!success)
+	 return false;
+   }
+   return true;
+}
+
+
+void hs_parse_args_(lua_State *L, int n_args, struct hs_arg *arguments)
+{
+   bool success = try_parse_args(L, n_args, arguments);
+   if (!success) {
+      lua_pushstring(L, "expected arguments of the form (");
+      for (int i=0; i<n_args; i++) {
+	 lua_pushstring(L, hs_type_to_string(arguments[i].type));
+	 lua_pushstring(L, ", ");
+      }
+      lua_pop(L, 1);
+      lua_pushstring(L, "); received (");
+      const int n_provided = lua_gettop(L);
+      for (int i=0; i<n_provided; i++) {
+	 lua_pushstring(L, lua_typename(L, lua_type(L, i+1)));
+	 lua_pushstring(L, ", ");
+      }
+      lua_pop(L, 1);
+      lua_pushstring(") instead");
+      lua_concat(L, 1 + (2*n_args) + (2*n_provided));
+      lua_error(L);
+   }
+}