Improve Binary Search Exercise: Rename Variable and Add Guard Validation

[rabestro]

Improve Binary Search Exercise: Rename Variable and Add Guard Validation

Problem Statement

The current Binary Search exercise uses a variable value, initialized with the -v option, without explicit handling in the code. This can confuse external readers of published solutions, as the source of this variable isn’t immediately clear.

To improve clarity and robustness:
1. Rename the value variable to target, making its purpose in the binary search more intuitive.
2. Add a test case that passes an empty parameter and expects a corresponding error message, encouraging students to add guard validation.

Proposed Changes

Rename value to target

• Update all references in the example implementation.
• Update test cases to use target instead of value.

Add Guard Validation Test Case

• Add a new test case to ensure students validate the presence of the variable.

Example:

awk -v target="" -f binary_search.awk input_file

Expected output (to stderr):

Error: 'target' variable not set.

Update the example implementation to include a BEGIN block for guard validation:

BEGIN {
    if (target == "") {
        print "Error: 'target' variable not set." > "/dev/stderr"
        exit 1
    }
    FS = ","
}

Deliverables

• Updated example implementation with the renamed variable and guard validation.
• Updated test cases to reflect the new variable name and include the guard validation check.

[IsaacG]

1. Remaining the variable would break existing solutions. I'm not sure there is much benefit.
2. Exercism explicitly opted to not add input validation to exercises so students can focus on the actual problem vs writing a bunch of validation over and over.

[glennj]

1. Good point about renaming.

2. This idea started in our code review session. I wrote

   One thing that I've always found troubling is the lack of visibility of the value variable. If that [initial] comment wasn't there, there would be no indication of where this magic variable comes from.

   What I'd like to see is that the input validation is provided in the stub already. Then, the BEGIN block would call out "I need this variable named value"

[IsaacG]

I commented on the forum. Let me know if you'd prefer to discuss here instead.

[glennj]

Let's stick to the forum