SoftwareMetrics

Goal

SoftwareMetrics compares different programming languages in order to determine which one is better than another according to a specific set of metrics.

Applying a series of tool on an algorithm written in different programming languages, we obtain a set of metrics necessary to make the comparisons between languages.

Usage

git clone --recurse-submodules -j8 https://github.com/SoftengPoliTo/SoftwareMetrics
make install
./analyzer.py -p <path_to_the_code_to_analyze>

To update submodules:

git submodule update --recursive --remote
make clean
make install

Used tools

Tokei

Used for: SLOC, LLOC, CLOC, BLANK

* Building: Ok
* Local installation: Ok

Can analyze either a single file or an entire directory

Rust Code Analysis

Used for: SLOC, PLOC, LLOC, CLOC, BLANK, NOM, CC, COGNITIVE, HALSTEAD, MI

* Building: Ok
* Local installation: Ok

Can analyze either a single file or an entire directory

Comparisons among different programming languages

To run the series of comparisons among the metrics produced by rust-code-analysis on some codes written in different programming languages, it is necessary to install json-diff:

1. Install npm as described here
2. Install json-diff following these instructions

At this point, the results of the comparisons can be obtained in this way:

./compare.py

Considered Metrics

• SLOC
• PLOC
• LLOC
• CLOC
• BLANK
• CC
• COGNITIVE
• Halstead
• MI
• NOM
• NARGS
• NEXITS
• CHANGE
• MPC
• NPM
• WMC
• C&K
• LCOM2
• CE

Implemented metrics

• SLOC: Source Lines of Code. It returns the total number of lines in a file.

• PLOC: Physical Lines of Code. It returns the number of instructions and comment lines in a file.

• LLOC: Logical Lines of Code. It returns the number of logical lines (statements) in a file.

• CLOC: Comment Lines of Code. It returns the number of comment lines in a file.

• BLANK: Blank Lines of Code. It returns the number of blank lines in a file.

• NOM: Number of Methods. It counts the number of methods in a file.

• NARGS: Number of Arguments. It counts the number of arguments of each method in a file.

• NEXITS: Number of Exit Points. It counts the number of exit points of each method in a file.

• CC: McCabe's Cyclomatic Complexity. It calculates the code complexity examining the control flow of a program.

• COGNITIVE: Cognitive Complexity. It is a measure of how difficult a unit of code is to intuitively understand.

• Halstead: It calculates the Halstead suite.

• MI: Maintainability Index. It is a suite to measure the maintainability of a code. It is calculated both on files and functions.

Metrics to be implemented

• CHANGE: It analyses different versions of the same code.

Class metrics (not to be implemented)

• MPC: Message Passing Coupling. It is a metric from the Li & Henry suite.

• NPM: Number of Public Methods. It returns the number of methods in a class declared as public.

• WMC: McCabe's Weighted Methods Count. It sums the CC of each methods in a class. Hence, it is a per-class calculated metric.

• C&K: Chidamber & Kemerer. It can be computed per-class only. Currently, we support only 4 of the 6 metrics defined by this metric suite.

• LCOM2: Lack of Cohesion 2. An alternative way to calculate LCOM by C&K.

• CE: Efferent Coupling. It can be computed per-class only.

Alternative metric names

• STAT: Statements. In scientific literature, LLOC applied only on methods/classes is better known with this name.