C++ Mathematical Expression Library (ExprTk) https://www.partow.net/programming/exprtk/index.html
diff --git a/exprtk.hpp b/exprtk.hpp
index f4a872d..1fbe8d9 100644
--- a/exprtk.hpp
+++ b/exprtk.hpp
@@ -2439,10 +2439,10 @@
Disallowed: .abc, abc.<white-space>, abc.<eof>, abc.<operator +,-,*,/...>
*/
if (
- (s_itr_ != initial_itr) &&
- !is_end(s_itr_ + 1) &&
- details::is_letter_or_digit(*s_itr_ + 1) &&
- ('_' != (*s_itr_ + 1))
+ (s_itr_ != initial_itr) &&
+ !is_end(s_itr_ + 1) &&
+ details::is_letter_or_digit(*(s_itr_ + 1)) &&
+ ('_' != (*(s_itr_ + 1)))
)
break;
}
diff --git a/readme.txt b/readme.txt
index 0c644fc..c2a9689 100644
--- a/readme.txt
+++ b/readme.txt
@@ -849,6 +849,48 @@
(09) Load Variable (w)
+Generally an expression in ExprTk can be thought of as a free function
+similar to those found in imperative languages. This form of pseudo
+function will have a name, it may have a set of one or more inputs and
+will return at least one value as its result. Futhermore the function
+when invoked, may cause a side-effect that changes the state the of
+host program.
+
+As an example the following is a pseudo-code definition of a free
+function that performs a computation taking four inputs, modifying one
+of them and returning a value based on some arbitrary calculation:
+
+ ResultType foo(InputType x, InputType y, InputType z, InputType w)
+ {
+ w = 2 * x^y + z; // Side-Effect
+ return abs(x - y) / z; // Return Result
+ }
+
+
+Given the above definition the following is a functionally equivalent
+version using ExprTk:
+
+ const std::string foo_str = " w := 2 * x^y + z; "
+ " abs(x - y) / z; ";
+
+ T x, y, z, w;
+
+ symbol_table_t symbol_table;
+ symbol_table.add_variable("x",x);
+ symbol_table.add_variable("y",y);
+ symbol_table.add_variable("z",z);
+ symbol_table.add_variable("w",w);
+
+ expression_t foo;
+ foo.register_symbol_table(symbol_table);
+
+ parser_t parser;
+ if (parser.compile(foo_str,foo))
+ {
+ foo.value();
+ }
+
+
(3) Parser
A component which takes as input a string representation of an
expression and attempts to compile said input with the result being an
@@ -1293,7 +1335,7 @@
In the example above, if the condition 'y < z' is true, then the
-consequent 'y + 1' will be evaluated, it's value will be returned and
+consequent 'y + 1' will be evaluated, its value will be returned and
subsequently assigned to the variable 'x'. Otherwise the alternative
'2 * z' will be evaluated and its value will be returned. This is
essentially the simplest form of an if-then-else statement, As simple
