MathDisplayExpr.mesa
Carl Waldspurger, August 23, 1986 2:35:40 pm PDT
Definitions for Mathematics Display Expressions
DIRECTORY
MathExpr USING [EXPR, AtomEXPR, CompoundEXPR, AtomClass, CompoundClass, MatrixClass],
MathBox USING [BOX],
MathTypes USING [Style],
MathRules USING [Size],
Rope USING [ROPE],
Imager USING [Context, Color];
MathDisplayExpr: CEDAR DEFINITIONS ~
BEGIN
Type Abbreviations from Imported Interfaces
ROPE: TYPE ~ Rope.ROPE;
EXPR: TYPE ~ MathExpr.EXPR;
AtomEXPR: TYPE ~ MathExpr.AtomEXPR;
CompoundEXPR: TYPE ~ MathExpr.CompoundEXPR;
BOX: TYPE ~ MathBox.BOX;
Style: TYPE ~ MathTypes.Style;
Size: TYPE ~ MathRules.Size;
AtomClass: TYPE ~ MathExpr.AtomClass;
CompoundClass: TYPE ~ MathExpr.CompoundClass;
MatrixClass: TYPE ~ MathExpr.MatrixClass;
Display Expression Type Definitions
A DisplayExpr is a MUTABLE math expression which is mapped to a viewer.
DisplayExpr: TYPE ~ REF DisplayExprRep; -- external abstract type
DisplayExprRep: TYPE; -- internal concrete rep
Selection Type Definitions
Selection: TYPE ~ RECORD[expr: DisplayExpr, color: Imager.Color];
Display Expression Constructors
MakeAtomicDisplayExpr: PROC[tag: ATOM, class: AtomClass, value: ROPE, relBox, absBox: BOX, parent: DisplayExpr ← NIL] RETURNS[DisplayExpr];
effects: Constructs and returns a new atomic display expression.
MakeCompoundDisplayExpr: PROC[tag: ATOM, class: CompoundClass, subExprs: LIST OF DisplayExpr, relBox, absBox: BOX, parent: DisplayExpr ← NIL] RETURNS[DisplayExpr];
effects: Constructs and returns a new compound display expression.
MakeMatrixDisplayExpr: PROC[tag: ATOM, class: MatrixClass, nRows, nCols: INT, elements: LIST OF DisplayExpr, relBox, absBox: BOX, openSym, closeSym, space: DisplayExpr, parent: DisplayExpr ← NIL]
RETURNS[DisplayExpr];
effects: Constructs and returns a new matrix display expression.
Parse/UnParse Routines
ASRopeFromDisplayExpr: PROC[expr: DisplayExpr] RETURNS[ROPE];
effects: Returns a ROPE in Dennis Arnon's AlgebraStructures form from expr.
DisplayExprFromExpr: PROC[expr: EXPR] RETURNS[DisplayExpr];
effects: Constructs and returns a new display expression from expr.
All Display formatting information is set to default values.
ExprFromDisplayExpr: PROC[expr: DisplayExpr] RETURNS[EXPR];
effects: Constructs and returns a new EXPR from expr.
Copy: PROC[expr: DisplayExpr] RETURNS[DisplayExpr];
effects: Returns a distinct copy of expr.
Selectors
Tag: PROC[expr: DisplayExpr] RETURNS[ATOM];
effects: Returns tag associated with expr.
Class: PROC[expr: DisplayExpr] RETURNS[ATOM];
effects: Returns class of expr.
GetSubExprs: PROC[expr: DisplayExpr] RETURNS[LIST OF DisplayExpr];
effects: Returns subexpressions for expr.
Returns NIL if no subexpressions exist.
List Operations
GetDisplayExpr: PROC[tag: ATOM, exprs: LIST OF DisplayExpr] RETURNS[DisplayExpr];
effects: Returns the DisplayExpr in exprs associated with tag.
SIGNALS exprNotFound if no association exists.
Format and Paint
Format: PROC[expr: DisplayExpr, size: Size] RETURNS[BOX];
modifies: expr
effects: expr is updated into a "paintable" form.
Returns a bounding box for expr.
SIGNALS unable[reason: ATOM] if Formatting can not be completed.
Paint: PROC[expr: DisplayExpr, context: Imager.Context, absBox: BOX,
selections: LIST OF Selection];
modifies: expr
effects: Displays expr in context, bounded by absBox.
Updates absolute bounding boxes (viewer coords).
SIGNALS unable[reason: ATOM] if Painting cannot be completed.
Selection Operations
DisplayExprFromCoords: PROC[expr: DisplayExpr, x, y: REAL] RETURNS[DisplayExpr];
effects: Returns the subexpression associated with coordinates [x, y] in expression expr.
SIGNALS noSelection if no association exists.
Selectable: PROC[expr: DisplayExpr] RETURNS[BOOL];
effects: Returns TRUE iff expr is selectable.
SelectableParent: PROC[expr: DisplayExpr] RETURNS[DisplayExpr];
effects: Returns the parent (enclosing expression) of expr.
SIGNALS noSelection if no selectable parent exists.
SelectableChild: PROC[expr: DisplayExpr] RETURNS[DisplayExpr];
effects: Returns a child expressions (subexpression) for expr.
SIGNALS noSelection if no selectable child exists.
SelectableSibling: PROC[expr: DisplayExpr] RETURNS[DisplayExpr];
effects: Returns the "next" sibling expression from expr.
SIGNALS noSelection if no selectable sibling exists.
Replace: PROC[expr, old, new: DisplayExpr] RETURNS[DisplayExpr];
effects: Returns a copy of display expression expr with new substituted for old.
caveats: Return value must be reformatted before Paint[]'ing.
Note that new is used (not a copy).
ReplacePair: TYPE ~ RECORD[old, new: DisplayExpr];
ReplaceN: PROC[expr: DisplayExpr, replacements: LIST OF ReplacePair] RETURNS[DisplayExpr];
effects: Returns a copy of display expression expr with
new substitured for old for each pair in replacements.
caveats: Return value must be reformatted before Paint[]'ing.
Note that the "new" components of replace pairs are used (not copies).
Signals & Errors
unable: ERROR[reason: ATOM];
noSelection: ERROR;
END.