Templates for types

[theodore-norvell]

Currently there doesn't seem to be a way to add types to variable declarations.

[theodore-norvell]

We need palette items for these templates.

[theodore-norvell]

See the Types in PLAAY documentation for the kinds of types.

We need the following new label classes.

• BoolTypeLabel, StringTypeLabel, NumberTypeLabel, IntTypeLabel, NatTypeLabel, NullTypeLabel, TopTypeLabel, BottomTypeLabel. No children.
• TupleTypeLabel. Any number of children. All children must be types or ExpressionPlaceHolders.
• LocationTypeLabel. One child which must be a type or ExpressionPlaceHolder.
• FunctionTypeLabel. Two children. Both must be a type or ExpressionPlaceHolder.
• FieldTypeLabel: 2 children. First must be an identifier or an ExpressionPlaceHolder. Second must be a type or ExpressionPlaceHolder.
• MeetTypeLabel, JoinTypeLabel: 2 or more children. All children must be types or ExpressionPlaceHolders.

In terms of how these should look (i.e. convert to html or svg)

• boolean type. Just a box (no border) with the unicode character 𝔹 (U+1D539)
• string type. Just a box (no border) with the unicode character S (U+1D54A)
• number type. Just a box (no border) with the unicode character ℚ (U+211A)
• int type. Just a box (no border) with the unicode character ℤ (U+2124)
• nat type. Just a box (no border) with the unicode character ℕ (U+2115)
• null type. Same symbol as the null literal, This is U+23DA
• top type. Just a box (no border) with a Down Tack symbol U+22A4
• bottom type. Just a box (no border) with an Up Tack symbol U+22A5
• tuple type. No border. Open parenthesis, operands separated by commas, close parenthesis.
• location type. Needs a border on left, bottom, and right sides.
• Field type. No border. A colon separates the two operands
• function type. Needs a border. The operands are separated by an rightwards arrow U+2192
• join type. Needs a border. The operands are separated by | (U+007C) symbols.
• meet type. Needs a border. The operands are separated by & (U+007C) symbols.

All borders and symbols should be the same colour. Let's try yellow to start. rgb(211,50,9)

[theodore-norvell]

In terms of editing, we need a new palette for types. So there will be an expression palette and type palette. These palettes can just be side-by-side.

Some of the editing actions can be shared by the two pallettes, for example, the "makeTupleNode" action of the treeManager can be invoked from either palette or from pressing the "(" key. The makeTupleNode function in treeManager currently does a replaceEngluf with one template. We can modify it by adding a second template that makes uses a TupleTypeLabel instead of a TupleLabel. If the first template fails, the second template will be tried. Since expressions are not allowed where types are allowed and conversely, this will work. For example if the current selection is a place where a type can go but an expression can not, hitting the "(" key will make a TupleTypeLabel( ExpPH, ExpPH ). But if the current selection is a place where an expression can go, hitting the "(" key will make a TupleType( ExpPH, ExpPH ) as it does currently.

We can have shared keyboard shortcuts as follows

• "(" Tuple or TupleType
• "\" Lambda expression or function type
• "&" and expression or meet type
• "|" or expression or join type
• "0" number literal or nat type
• "1" number literal or int type
• "2"--"9" number literal or number type
• '"' string literal or string type
• "?" if expression or boolean type
• ";" location declaration or change con declaration to location declaration or location type

also the following keyboard shortcut is not shared

• ":" field type

The following pairs of palette items can share their behaviour (i.e. they invoke the same action in the treeManager, which then uses a choice of templates or a choice of edits (two edits can be combined with the alt function from the edits module to make an edit that does one or the other of them).

• null expression and null type
• tuple expression and tuple type
• lambda expression and function type
• location declaration and location type
• string literal and string type
• number literal and number type
• the two boolean literals and boolean type

[theodore-norvell]

Made new actions for keyboard so that the buttons are single purpose (either type or expression) by the keyboard shortcuts are alternatives.