{ Parse and Translate an Expression }

procedure Expression;

begin

FirstTerm;

while IsAddop(Look) do begin Push;

case Look of

+: Add;

Subtract;

end; end; end;

{ Recognize and Translate a Relational "Equals" }

procedure Equal;

begin

Match(=);

Expression;

PopCompare;

SetEqual; end;

{ Recognize and Translate a Relational "Less Than or Equal" }

procedure LessOrEqual;

begin

Match(=);

Expression;

PopCompare;

SetLessOrEqual; end;

{ Recognize and Translate a Relational "Not Equals" }

procedure NotEqual;

begin

Match(>);

Expression;

PopCompare;

SetNEqual; end;

{ Recognize and Translate a Relational "Less Than" }

procedure Less;

begin

Match(<); case Look of

=: LessOrEqual; >: NotEqual; else begin

Expression; PopCompare; SetLess; end;

end; end;

{ Recognize and Translate a Relational "Greater Than" }

procedure Greater;

begin

Match(>);

if Look = = then begin

Match(=);

Expression;

PopCompare;

SetGreaterOrEqual;

end else begin

Expression;

PopCompare;

SetGreater; end; end;

{ Parse and Translate a Relation }

procedure Relation; begin

Expression;

if IsRelop(Look) then begin Push;

case Look of =: Equal; <: Less; >: Greater; end; end; end;

{ Parse and Translate a Boolean Factor with Leading NOT }

procedure NotFactor;

begin

if Look = ! then begin MatchC!); Relation;

NotIt;

end else

Relation;

end;

{ Parse and Translate a Boolean Term }

procedure BoolTerm;

begin

NotFactor;

while Look = & do begin Push;

Matches); NotFactor; PopAnd; end; end;

{ Recognize and Translate a Boolean OR }

procedure BoolOr;

begin

Match(l);

BoolTerm;

PopOr; end;

{ Recognize and Translate an Exclusive Or }

procedure BoolXor;

begin

Match(~);

BoolTerm;

PopXor; end;

{ Parse and Translate a Boolean Expression }

procedure BoolExpression;

begin

BoolTerm;

while IsOrOp(Look) do begin Push;

case Look of

l: BoolOr;

BoolXor;

end; end; end;

{ Parse and Translate an Assignment Statement } procedure Assignment; var Name: string; begin

Name := Value;

Match(=);

BoolExpression;

Store(Name); end;

{ Recognize and Translate an IF Construct } procedure Block; Forward;

procedure DoIf; var L1, L2: string; begin

BoolExpression;

L1 := NewLabel;

L2 := L1;

BranchFalse(L1);

Block;

if Token = l then begin

L2 := NewLabel; Branch(L2); PostLabel(L1); Block;