Parametric polymorphism: Difference between revisions

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binary_tree_of "node-type" = ("node-type",(binary_tree_of "node-type")%Z)%drWZwlwAZ</lang>

(The %Z type operator constructs a "maybe" type, i.e., the free union of its operand type

(The <code>%Z</code> type operator constructs a "maybe" type, i.e., the free union of its operand type

with the null value. Others shown above are standard stack manipulation primitives, e.g. d (dup) and w (swap), used to build the type expression tree.) At the other extreme, one may construct an equivalent parameterized type in

with the null value. Others shown above are standard stack manipulation primitives, e.g. <code>d</code> (dup) and <code>w</code> (swap), used to build the type expression tree.) At the other extreme, one may construct an equivalent parameterized type in

point-free form.

<lang Ursala>binary_tree_of = %-hhhhWZAZ</lang>

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example = (binary_tree_map "s". "s"--"s") x</lang>

Type signatures are not associated with function declarations, but

Type signatures are not necessarily associated with function declarations, but

have uses in the other contexts such as assertions and compiler directives

(e.g., #cast). Here is the output.

(e.g., <code>#cast</code>). Here is the output.

<pre>

'foofoo': ('barbar': (),'bazbaz': ())