Code Explainer
Analyze and explain code structure and elements
Input Information
Result
Code Explainer is a developer assistant that, when you paste programming code, automatically analyzes and explains its structure and elements through regular-expression (RegExp) based pattern matching. It comprehensively analyzes functions/method definitions, variable/class declarations, control structures, comments, and code statistics to help you grasp the overall structure at a glance.
It supports five major languages — JavaScript, Python, Java, HTML, and CSS — each with separately optimized RegExp patterns and keyword lists. It is useful for beginners just starting programming, developers learning a new language, and senior developers who must review legacy code.
It is not a full AI-based code analysis, but it is effective for quickly grasping code structure in a review meeting, understanding the components of open-source code you are studying, or checking the complexity of your own code. Selecting the language before analysis gives language-optimized results.
Results are structured by category — functions/methods list, comments, control structures, variable declarations, code statistics — and the full analysis can be copied to the clipboard at once for documentation or sharing with teammates.
Term Glossary
- Regular Expression (RegExp)
- Syntax for finding or classifying patterns in strings. This tool detects each language’s function declarations, comments, and keyword patterns via RegExp.
- Control Flow
- Statements that control the execution flow of code — if, for, while, switch, try/catch — determining branching and repetition.
- Keyword
- Reserved words with special meaning in a programming language. Each language has its own keyword list, used to understand code structure.
Code Analysis Algorithm:
This tool uses a regular-expression (RegExp) based pattern-matching algorithm to analyze code. Specialized RegExp patterns and keyword lists are defined per language, detecting and classifying code elements.
Step 1 - Function/method detection: Detect each language’s function declaration pattern via RegExp.
Step 2 - Comment extraction: Detect each language’s comment syntax and extract the comment content.
Step 3 - Keyword and control-structure analysis: Compare the code against a predefined keyword list to detect used keywords.
Step 4 - Variable/class declaration detection: Extract code lines containing variable/class declaration keywords.
Step 5 - Code statistics: Compute basic statistics: total lines, character count, blank lines, and language used.
Patterns by supported language:
- JavaScript: function, const/let/var arrow functions, import/export, async/await
- Python: def, class, self, lambda, try/except, with/as
- Java: public/private/protected, static, class, interface, try/catch
- HTML: all HTML tags, attributes, comments
- CSS: selectors, properties, media queries, @ rules
Effective Usage and Tips:
1. Always select the programming language
Before entering code, always select the language from the dropdown. Function patterns, keyword lists, and comment syntax differ by language, so the correct choice directly affects accuracy.
2. Enter a sufficient amount of code
Rather than 1–2 short lines, enter a code block with several functions or a whole file for more meaningful results. At least 10 lines is recommended.
3. Use it for code review
Using this tool before a code review meeting lets you grasp the structure quickly.
4. Analyze code you are studying
When learning a new language or framework, pasting open-source or example code helps you quickly understand its structure and elements.
5. Document the analysis results
The "Copy explanation" button copies the entire analysis to the clipboard.
6. Understand the limits of pattern-based analysis
Because it is RegExp-based pattern matching, it does not perform semantic analysis (meaningful variable names, logic correctness, performance analysis, etc.).
7. Analyze mixed-language code separately
Code mixing JavaScript and Python should be split by language and analyzed separately.