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, flavor:
ATOM ← $AS]
RETURNS[
ROPE];
effects: Returns a ROPE in selected format
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];