Syncalc supports the four basic arithmetic operations and negation, as well as several functions. Expressions can be parenthesized in order to change the default order of evaluation. Spaces are not significant, except that the division operator must be surrounded by blanks so that it is not mistaken for part of a file name. Syncalc evaluates expressions containing file names, constants, and variables. When syncalc sees a file name, it determines if the file is a passband or a spectrum, and then reads it interpolated onto the given wavelength grid.
Constants are either numbers or strings.
String constants are not surrounded by quotation marks. Numeric constants are interpreted as real numbers and all mathematical operations between file names and constants are legal. Variables may occur in an expression wherever a numeric constant is legal. Constants, variables, and passbands have a degree of zero. Spectra have a degree of one.