README

ParamParser

A minimal command-line parameter parser for Delphi / Object Pascal applications.

Features

• 🪶 One file, no dependencies. It only needs Classes, SysUtils and Math.
• 🏳️ Flags: -d or --debug return 'true'.
• 🧩 Valued parameters: -t value or --target value return 'value'.
• 🔀 Short and long names: look up -t and --target in one call.
• 🎯 Exact matching: -t does not match --test, and it does not match a value that contains -t.

Installation

1. Copy paramparser.pas into your project folder, or add its folder to your unit search path.
2. Add ParamParser to your uses clause.

[!NOTE] The unit does not declare a compiler mode. With Free Pascal / Lazarus, compile it in objfpc or delphi mode, either from the project options or with -Mobjfpc on the command line, so that Result is available.

Quick start

program Demo;

{$mode objfpc}{$H+}

uses
  Classes, ParamParser;

var
  Params: TStringList;
begin
  Params := TStringList.Create;
  try
    ParseParams(Params);

    WriteLn('Target: ', GetParam(Params, 't', 'target'));
    WriteLn('Debug:  ', GetParam(Params, 'd', 'debug'));
  finally
    Params.Free;
  end;
end.

$ ./demo -t production --debug
Target: production
Debug:  true

$ ./demo --target staging
Target: staging
Debug:  false

API

ParseParams

procedure ParseParams(var ParamList: TStringList);

Reads the parameters passed to the program (ParamStr(1) to ParamStr(ParamCount)) and adds them to ParamList.

• A parameter that starts with - or -- and is followed by a parameter that does not start with - is stored with its value, as -t|value.
• Any other parameter that starts with - or -- is stored as a flag, as -d.
• Parameters that do not start with - and do not follow a parameter name are ignored.

[!IMPORTANT] The caller creates ParamList before the call and frees it afterwards.

GetParam

function GetParam(var ParamList: TStringList; ParamName: String;
  LongParamName: String): String;

Looks up a parameter by its short name (-ParamName) or its long name (--LongParamName). Pass the names without the dashes.

The result is always a String. Convert it as needed, for example with StrToBool or StrToIntDef.

Behavior and limitations

• A value cannot start with -. In -n -5, -5 is read as another parameter, so -n becomes a flag.
• Combined short flags such as -abc are not split. -abc is a single parameter named abc.
• The --name=value syntax is not supported. Use --name value.
• Names are case-sensitive: -T and -t are different parameters.
• If a parameter is passed more than once, GetParam returns the first one.

License

Distributed under the MIT License. © 2025 Rodrigo Peetz.