This is Markdown file directive3.md

Directives are HTML comments and are not rendered. To see the directives press Edit on GitHub and then the Raw button.

share-names and clear-names directives.

First a normal test case with no directives. This generates a test case. The name not_shared is local to the function test_code_13_output_17().

not_shared = "Hello World!"
print(not_shared)

Hello World!

This verifies not_shared is not visible.

try:
    print(not_shared)
except NameError:
    pass
else:
    assert False, "did not get expected NameError"

Share the names assigned here with later Python code blocks.

The share-names directive makes the names assigned here global to the test module. The names are visible to all Python code blocks occurring later in the Markdown source file. The code assigns the names string, x, y, z, grades, and the function incrementer(). Place the <!--phmdoctest-share-names--> directive in the Markdown file.

import string

x, y, z = 77, 88, 99

def incrementer(x):
    return x + 1

grades = ["A", "B", "C"]

This test case shows the shared names are visible.

print("string.digits=", string.digits)
print(incrementer(10))
print(grades)
print(x, y, z)

expected output:

string.digits= 0123456789
11
['A', 'B', 'C']
77 88 99

This test case modifies grades.

The objects created by the share-names code block can be modified and blocks run afterward will see the changes.

grades.append("D")

This test case sees the modified grades.

print(grades == ["A", "B", "C", "D"])

expected output:

True

This test case shares another name.

hex_digits = string.hexdigits
print(hex_digits)

A Python block with the share-names directive can have an output block.

0123456789abcdefABCDEF

Use clear-names directive to un-share.

First notice that hex_digits shared by the last test case is visible. The clear-names directive un-shares any previously shared names. The names will no longer be visible to Python code blocks occurring later in the Markdown source file. The clearing does not happen until after the test case runs. This test case is the same as the previous test case to show that mylist is still visible.

print("Names are cleared after the code runs.")
print(grades == ["A", "B", "C", "D"])
print(hex_digits)

expected output:

Names are cleared after the code runs.
True
0123456789abcdefABCDEF

Here we show that grades and digits are no longer visible.

try:
    print(grades)
except NameError:
    pass
else:
    assert False, "expected NameError for grades"
try:
    print(hex_digits)
except NameError:
    pass
else:
    assert False, "expected NameError for hex_digits"