Unlike word processors or
non-Mathematica
technical systems, semantic-faithful typesetting enables typeset
expressions to be
input, selected appropriately, edited, and then evaluated directly.
Semantic-faithful typesetting (SFT) combines the elegance of traditional
mathematical typography with the precision of a computer language. SFT is
unique to Mathematica and its capabilities are immediately
apparent: expressions input in a fully typeset form
can be evaluated, evaluations are automatically typeset--and can then
subsequently be edited, re-evaluated, exported, and so
forth.
Delivering SFT is nontrivial (it required seven years of Wolfram
Research development) because some mathematical notation is ambiguous,
there are many cases where one mathematical meaning has multiple
representations, and because of the complexity of working with
expressions from a standard keyboard. Other difficult issues include
line-breaking, subexpression selection and evaluation, and heuristic
conversion from traditional non-semantic typesetting systems such as
TeX.