Call a function: Difference between revisions

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 <lang PicoLisp>(setq A (+ 3 4)  B (* 3 4))</lang>
 i.e. the first argument 'A' is not evaluated, the second evaluates to 7, 'B' is not evaluated, then the fourth evaluates to 12.
+=={{header|Python}}==
+<lang python>def no_args():
+    pass
+# call
+no_args()
+def fixed_args(x, y):
+    print('x=%r, y=%r' % (x, y))
+# call
+fixed_args(1, 2)        # x=1, y=2
+def opt_args(x=1):
+    print(x)
+# calls
+opt_args()              # 1
+opt_args(3.141)         # 3.141
+def var_args(*v):
+    print(v)
+# calls
+var_args(1, 2, 3)       # (1, 2, 3)
+var_args(1, (2,3))      # (1, (2, 3))
+var_args()              # ()
+## Named arguments
+fixed_args(y=2, x=1)    # x=1, y=2
+## As a statement
+if 1:
+    no_args()
+## First-class within an expression
+assert no_args() is None
+def return_something():
+    return 1
+x = return_something()
+def is_builtin(x):
+	print(x.__name__ in dir(__builtins__))
+# calls
+is_builtin(pow)         # True
+is_builtin(is_builtin)  # False
+## A subroutine is merely a function that has no explicit
+## return statement and will return None.
+## Python uses "Call by Object Reference".
+## See, for example, http://www.python-course.eu/passing_arguments.php
+## For partial function application see:
+##   http://rosettacode.org/wiki/Partial_function_application#Python</lang>
 =={{header|REXX}}==