Freon Documentation (version 0.5.0)

The Editor Definition Files

In an editor definition file (.edit file) you can define a Freon editor by providing extra information for each concept or interface in your language. Currently, you can define the following three items per concept or interface.

  • A projection, which is how the concept is shown in the editor.
  • An optional trigger, which is the key or keys your user needs to type to create a new instance of the concept.
  • An optional symbol, which is only used for binary expressions. It is the character or character string that represents the operator. When the symbol is not present, the trigger will be used for this purpose.

You cannot create a projection for either a binary expression concept or a limited concept. The editor provides extra support for expressions, which cannot be done if a user defined projection is provided. Limited concepts are blocked, because the user of the editor can use the instances of the limited concept solely as references.

The projection is always the first
For every concept or interface you have to define the projection before the trigger and/or symbol.

Named Editors or Projection Sets

Editors can be named, and you can define multiple editors. A named editor defines a set of projections that are coordinated to operate together. These sets can be switched on and off dynamically, thus changing the appearance of the model in the editor. the appearance of the model in the editor.

For instance, if you define all table projections under the same editor name, then your user can switch from viewing objects as lists to viewing them as tables. Or, in another example, you could have an editor (or projection set) that shows only part of the properties of some concepts, whereas another editor shows all properties. This makes it possible to cater for different types of users.

Projections may specifically request that a property is displayed using a projection from a named editor. For this see Including a Property Projection from Another Editor.

The Default Editor and Defaults for Every Concept

Because there has to be an editor that can be used as fallback when all other editors are switched off, an editor with the name default is generated in case it is not provided. If the default editor is provided but incomplete, i.e. it does not define a projection for all concepts, projections will be generated for the missing concepts. So, upon generation the default editor is always complete.

For instance when no projection is provided for the concept BaseProduct, the concrete syntax for instances of this concept will be using the name of the concepts and its properties as keywords, and any list property will be shown as a vertical list, which is shown more or less by the following grammar rule.

// docu-project/defs/language-main.ast#L24-L28

concept BaseProduct {
    name: identifier;           // internal name
    theme: InsuranceTheme;      // the 'kind' of insurance
    parts: InsurancePart[];     // all parts of this product
BaseProduct = 'BaseProduct' identifier '{'
'theme' InsuranceTheme
'}' ;

Precedence of Editors

The named editors are ordered; the order can be indicated by adding a precedence to the editor. The projections are found based on this order. The default editor is always the last (i.e. its precedence is 0). If a box/projection for a concept is not present in the editor with the highest precedence, then the next editor is searched for a projection for the concept and so on, till the default editor is reached.

When you omit the precedence, Freon will assign one based on the order in which the files are read, which normally is alphabetically. However, we cannot guarantee any specific order.

Each editor can be defined in multiple files
Every .edit file that is encountered in the folder that holds your definitions, will be read during the generation. When the editor in multiple files has the same name all information will be combined into a single editor. The precedence needs to be added only once, but in case you add it multiple times, the numbers are required to be equal.
// docu-project/defs/editor-tables.edit#L1-L5

/* This file contains the table definition in a separate editor / projection group.
This enables the user to switch tables on and off. */

editor tables precedence 4

Standard Boolean Keywords

Next to the concrete syntax definitions for concepts and interfaces, you can define the keywords to be used for the boolean true and false values. Note that this can be done once in the complete set of editors. It should be part of an editor called default. In the example below, the user will view the string YES whenever a boolean property has the value true, and likewise NO will be shown for the value false.

// docu-project/defs/editor-main-default.edit#L5-L5

boolean [YES | NO] // the strings used to display a boolean value

The standard keywords can be overwritten per property. See Boolean Keyword Projections.

Reference Separator

References to other objects may consist of a series of names, like The string used to separate these names (in the example ”:”) can be set, but, like the boolean values, only once for the complete set of editors, in the editor called default.

// docu-project/defs/editor-main-default.edit#L7-L7

referenceSeparator [:] // the string that separates the names in a path name, e.g. pack1:cls3:part

Example .edit File

A complete .edit file could look like this.

// docu-project/defs/editor-main-default.edit#L1-L52

/* This file contains the default editor definition. */

editor default

boolean [YES | NO] // the strings used to display a boolean value

referenceSeparator [:] // the string that separates the names in a path name, e.g. pack1:cls3:part

// both modelunits show a single concept
Part {[ ${self.part} ]}
Product {[ ${self.product} ]}

BaseProduct {[
    Base Products ${name} for ${theme}

    Insurance Part ${}
        risk assessment: ${self.statisticalRisk}
        maximum payout: ${self.maximumPayOut}
        is approved: ${self.isApproved}

InsuranceProduct {[
    Insurance Product ${name} ( public name: ${productName} ) USES ${basedOn horizontal separator[, ]}
        Themes: ${themes horizontal separator[, ]}
        Premium: ${advertisedPremium} per ${nrPremiumDays}
        Insured risks:
            ${parts vertical terminator [;]}
            [? Risk adjusted by = ${riskAdjustment} ]
            calculated premium: ${calculation}
        [?Helper functions:
            ${helpers vertical}]

CalcFunction {
        ${name} ( ${parameters horizontal separator[,]} ): ${declaredType} {
Description {
Parameter {
     [${name} : ${declaredType}]