Enhancement: Add Boolean expressions to all logic gates in Chapter 4

[haaasini01]

Fixes #476

Changes done:

• Added standard Boolean expressions for all gates (AND, OR, NOT, XOR, NAND, NOR, XNOR)
• Updated truth table headers: Input 1 → A (Input 1), Input 2 → B (Input 2), Output → Y (Boolean Expression)

Screenshots:

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Summary by CodeRabbit

Documentation

• Expanded logic gate descriptions with explicit Boolean expressions for each gate type
• Restructured truth tables with clearly labeled inputs (A, B) and corresponding output values
• Enhanced readability through improved formatting, spacing, and better visual organization of content
• Updated table references and captions for consistency throughout the chapter

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

Documentation update to Chapter 4 (Gates) adding explicit Boolean expressions for logic gates (AND, OR, NOT, XOR, NAND, NOR, XNOR) and expanding truth tables with labeled inputs and outputs. No executable code changes.

Changes

Cohort / File(s)	Summary
Logic Gate Documentation Enhancement docs/chapter4/4gates.md	Added Boolean expressions for each gate type; expanded truth tables with labeled A, B inputs and explicit Y output expressions; updated table captions and headings; improved formatting with line breaks for readability

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

Pre-merge checks and finishing touches

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: adding Boolean expressions to logic gates in Chapter 4, which aligns perfectly with the changeset and linked issue #476.
Linked Issues check	✅ Passed	The pull request successfully addresses all coding requirements from issue #476: adds Boolean expressions for all seven gates (AND, OR, NOT, XOR, NAND, NOR, XNOR) and updates truth table headers as specified.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to the linked issue #476 objectives; documentation enhancements to add Boolean expressions and update table formatting are entirely within scope with no extraneous modifications.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

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Actionable comments posted: 0

🧹 Nitpick comments (2)

docs/chapter4/4gates.md (2)

61-67: Add blank lines before tables for proper Markdown formatting.

Tables should be surrounded by blank lines per Markdown best practices (MD058). Add a blank line before the table captions at line 61 and line 90 (and check other table instances in the file).

🔎 Proposed fix for AND gate table formatting

 AND gate gives a HIGH output only if all input values are HIGH.  
 **Boolean Expression:** `Y = A · B`  
+
 Table 4.25: Two-input AND gate truth table
 | A (Input 1) | B (Input 2) | Y = (A · B) |

Also applies to: 90-97

---

170-171: Remove redundant phrase "connected together."

The phrase "connected together in series" is redundant; simplify to "connected in series."

🔎 Proposed fix

-NAND gate, a combination of an AND gate and a NOT gate connected together in series, produces the inverted output of an AND gate––produces a LOW output when all the inputs are HIGH.  
+NAND gate, a combination of an AND gate and a NOT gate connected in series, produces the inverted output of an AND gate––produces a LOW output when all the inputs are HIGH.  

📜 Review details

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between bace6c5 and eadc3e8.

📒 Files selected for processing (1)

• docs/chapter4/4gates.md

🧰 Additional context used

🪛 LanguageTool

docs/chapter4/4gates.md

[style] ~170-~170: This phrase is redundant. Consider writing “connected”.
Context: ...mbination of an AND gate and a NOT gate connected together in series, produces the inverted output...

(CONNECT_TOGETHER)

🪛 markdownlint-cli2 (0.18.1)

docs/chapter4/4gates.md

62-62: Tables should be surrounded by blank lines

(MD058, blanks-around-tables)

🔇 Additional comments (1)

docs/chapter4/4gates.md (1)

58-67: Boolean expressions and truth tables are mathematically correct.

All gates (AND, OR, NOT, XOR, NAND, NOR, XNOR) have accurate Boolean expressions and truth table values. The column header updates ("A (Input 1)", "B (Input 2)", "Y = (operation)") clearly align inputs and outputs with their expressions, improving readability for users.

Also applies to: 87-97, 116-124, 143-153, 170-180, 199-209, 228-238