2IMP20-QL

Introduction

QL is a simple Domain Specific Language for questionaires that was developed for the Generic Language Theory course (2IMP20) at the Eindhoven University of Technology.

Supported Syntax

• Variable types boolean, integer, and string
• Simple Questions that require user input: "<string|Description>" <string|VariableName>: <type|VariableType>
• Computed Questions that operate on previously defined variables: "<string|Description>" <string|VariableName>: <type|VariableType> = <type|Operation>
• If-blocks: if (<boolean|Guard>) { }
• If-else-blocks: if (<boolean|Guard>) { } else { }
• Blocks: { }

Example

form codeExample {
    "What is your name?" name: string
    
    "What is your age?" age: integer
    
    if (age >= 16) {
       "Have you earned your driver's license?" license: boolean
       
       if (license) {
           "At what age did you earn your driver's license?" driverAge: integer
           
           "You have had your driver's license for this many years: " years: integer = driverAge - age
       }
    } else {
       if (age >= 14) {
           "Don't forget that you can earn your diver's license when you're this old in the Netherlands:" minLicenseAge: integer = 16
       }
    }
}

Supported Editor Features

• Code highlighting
• Type Checking
  • References to undefined questions
  • Duplicate question declarations with different types
  • Conditions that are not of the type boolean
  • Operands of invalid type to operators
  • Duplicate question descriptions (shows a warning)
• Flattening a questionaire (right-click in the editor)
• Renaming a variable (right-click in the editor)
• Compiling to Javascript/HTML (save any .ql-file and look for the generated JS/HTML files in the same directory as the .ql-file)

Known Problems

The following errors are not reported:

• A variable is used outside its scope
• A variable is used before it is defined

Execution

To run the IDE, open any source file and then open a new Rascal terminal. Type import IDE; and then main();. Opening any .ql-file now utilises the IDE.

Required Software

The following software was used to develop QL. Note that higher versions will probably also work, though those were untested.

• Eclipse (4.13.0)
• Rascal Plugin for Eclipse (0.16.2; Stable). Can be installed in Eclipse using the Help -> Install New Software option.