Contains extern "C" function definitions for linking this library
against projects in different languages. Not intended for use in
other Rust projects.
Solves an equation given as a string for a SINGLE unknown variable.
This function infers the unknown variable from the given expression,
using a new default ContextHashMap to account for common constants
and functions.
Solves an equation given as a string for the SINGLE
unknown that is inferred based on the context and the given equation
string. The given context must contain all known symbols in the
equation but NOT the variable that is to be solved for.
E.g. the context for "x + sin(y) = 9" must define a value for "y"
and "sin", but NO value for "x" if "x" is the variable to be solved for.