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Diffstat (limited to 'miralib/manual/19')
| -rw-r--r-- | miralib/manual/19 | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/miralib/manual/19 b/miralib/manual/19 new file mode 100644 index 0000000..b3cb620 --- /dev/null +++ b/miralib/manual/19 @@ -0,0 +1,18 @@ +_T_y_p_e_ _s_y_n_o_n_y_m_ _d_e_c_l_a_r_a_t_i_o_n_s + +These permit the user to introduce a new name for an already existing +type, e.g. + string == [char] +type synonyms are entirely transparent to the typechecker (it best to +think of them as being just macros). For obvious reasons, recursive type +synonyms are not permitted. + +It is also possible to introduce a synonym for a type forming operator, +by introducing generic type variable as parameters of the definition, +e.g. + invt * ** == (*->**)->(**->*) + +So within a script containing the above two `==' definitions, the type +`invt num string' will be shorthand for + (num->[char])->([char]->num) + |