Added TE_FLOAT preprocessor flag to use float instead of double for t…

…he parser's data type.

README.md

@@ -148,6 +148,7 @@ The following are changes from the original TinyExpr C library:
 - Added `set_constant()` function to find and update the value of a constant (custom) variable by name.
   (In this context, a constant is a variable mapped to a double value in the parser, rather than mapped to a runtime variable.)
 - Added `get_constant()` function to return the value of a constant (custom) variable by name.
+- Added `TE_FLOAT` preprocessor flag to use `float` instead of `double` for the parser's data type.
 - Binary search (i.e., `std::set`) is now used to look up custom variables and functions (small optimization).
 - You no longer need to specify the number of arguments for custom functions; it will deduce that for you.
 - The position of an error when evaluating an expression is now managed by the `te_parser` class and accessible via `get_last_error_position()`.

docs/manual/28-CompileTimeOptions.Rmd

@@ -1,5 +1,15 @@
 # Compile-time Options
 
+## `TE_FLOAT` {-}
+
+`double` is the default data type used for the parser's variable types, parameters, and return types.
+For embedded environments that require `float`, compile with `TE_FLOAT` defined to use `float` instead.
+
+When using this option, it is recommended to use the helper typedef `te_type`.
+This will map to either `float` or `double` (depending on whether `TE_FLOAT` is defined).
+By defining your functions and variables with `te_type`,
+you won't need to replace `double` and `float` if needing to change this compiler flag.
+
 ## `TE_POW_FROM_RIGHT` {-}
 
 By default, *TinyExpr++* does exponentiation from left to right. For example: