  We construct a logic-enriched type theory LTTW that corresponds closely to
the predicative system of foundations presented by Hermann Weyl in Das
Kontinuum. We formalise many results from that book in LTTW, including Weyl's
definition of the cardinality of a set and several results from real analysis,
using the proof assistant Plastic that implements the logical framework LF.
This case study shows how type theory can be used to represent a
non-constructive foundation for mathematics.
