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Swiss-army knife for D source code
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DScanner is a tool for analyzing D source code

Building and installing

First make sure that you have all the source code. Run git submodule update --init --recursive after cloning the project.

To build DScanner, run make (or the build.bat file on Windows). The build time can be rather long with the -inline flag on front-end versions older than 2.066, so you may wish to remove it from the build script. The makefile has "ldc" and "gdc" targets if you'd prefer to compile with one of these compilers instead of DMD. To install, simply place the generated binary (in the "bin" folder) somewhere on your $PATH.


The following examples assume that we are analyzing a simple file called helloworld.d

import std.stdio;
void main(string[] args)
    writeln("Hello World");

Token Count

The "--tokenCount" or "-t" option prints the number of tokens in the given file

$ dscanner --tokenCount helloworld.d

Import Listing

The "--imports" or "-i" option prints a listing of modules imported by the given source file.

$ dscanner --imports helloworld.d

Syntax Check

The "--syntaxCheck" or "-s" option prints a listing of any errors or warnings found while lexing or parsing the given source file. It does not do any semantic analysis and it does not compile the code.

Style Check

The "--styleCheck" or "-S" option runs some basic static analysis checks against the given source files.


By default all checks are enabled. Individual checks can be enabled or disabled by using a configuration file. Running dscanner --defaultConfig will generate a default configuration file and print the file's location. The "--config" option will allow you to specify the path to a configuration file if you do not want to use the one created by the "--defaultConfig" option.

Implemented checks

  • Old alias syntax (i.e "alias a b;" should be replaced with "alias b = a;").
  • Implicit concatenation of string literals.
  • Complex number literals (e.g. "1.23i").
  • Empty declarations (i.e. random ";" characters).
  • enum array literals in struct/class bodies.
  • Avoid Pokémon exception handling.
  • opCmp or opEquals, or toHash not declared "const".
  • Format numbers for readability.
  • delete keyword is deprecated.
  • "fish operators" (floating point operators) are deprecated.
  • Left side of a foreach or foreach_reverse range expression is larger than the right.
  • Left side of a slice expression is larger than the right.
  • Variable, struct, class, union, module, package, and interface names that do not comply with Phobos style guidelines.
  • Struct constructors that have a single parameter that has a default argument.
  • Assign expressions where the left side of the '=' operator is the same as the right.
  • 'if' statements where the 'else' block is the same as the 'if' block.
  • ||, &&, and == expressions where the left and right sides of the operator are identical.
  • && and || expressions where the order of operations is confusing.
  • Unused variables.
  • Unused parameters (check is skipped if function is marked "override").
  • Duplicate attributes.
  • Declaring opEquals without toHash.
  • Undocumented public declarations.
  • Subtraction from .length properties. (These may be unsigned and could lead to integer underflow)
  • Class, struct, and union member variables whose names conflict with built-in type properties.
  • Confusing asm syntax.
  • Placement of const, immutable, or inout before a function return type instead of after the parameters.
  • Functions in interface declarations redundantly marked 'abstract'.


  • Assigning to foreach variables that are not "ref".
  • Unused imports.
  • Variables that are never modified and not declared immutable.
  • Assignment in conditionals


The "--report" option writes a JSON report on the static analysis checks document above to standard output. This file is usually used by the D plugin for SonarQube located here.

Find Declaration

Ack, grep, and The Silver Searcher are useful for finding usages of symbols, but their signal to noise ratio is not very good when searching for a symbol's declaration. The "--declaration" or "-d" options allow you to search for a symbols declaration. For example:

$ dscanner -d TokenStructure

Line of Code Count

The "--sloc" or "-l" option prints the number of lines of code in the file. Instead of simply printing the number of line breaks, this counts the number of semicolon, while, if, do, else, switch, for, foreach, foreach_reverse, default, and case tokens in the file.

$ ./dscanner --sloc helloworld.d

Syntax Highlighting

The "--highlight" option prints the given source file as syntax-highlighted HTML to the standard output. The CSS styling is currently hard-coded to use the Solarized color scheme.

No example. It would take up too much space

CTAGS output

The "--ctags" or "-c" option generates CTAGS information and writes it to the standard output. When used with the "--recursive", "-R", or "-r" option, CTAGS information will be generated for a specified directory and all of its sub-directories.

$ dscanner --ctags helloworld.d
!_TAG_FILE_AUTHOR   Brian Schott
main    helloworld.d    3;" f   arity:1

CTAGS output uses the following tag kinds:

  • g -- enum declarataion
  • e -- enum member
  • v -- variable declaration
  • i -- interface declaration
  • c -- class declaration
  • s -- struct declaration
  • f -- function declaration
  • u -- union declaration
  • T -- template declaration

More information on the CTAGS format can be found here.


The "--outline" option parses the given D source file and writes an simple outline of the file's declarations to stdout.

AST Dump

The "--ast" or "--xml" options will dump the complete abstract syntax tree of the given source file to standard output in XML format. JSON output is planned but not yet implemented.

$ dscanner --ast helloworld.d
<functionDeclaration line="3">
<type pretty="void">
<type pretty="string[]">
<typeSuffix type="[]"/>
<stringLiteral>Hello World</stringLiteral>
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