-- ParserGraphs.mesa
-- last edit     November 1, 1984 3:41:32 pm PST
-- Sturgis, April 1, 1986 2:17:06 pm PST

DIRECTORY
GrammarBasic USING[Grammar, Symbol];


ParserGraphs: CEDAR DEFINITIONS  =

BEGIN OPEN GrammarBasic;

-- These graphs are used to represent LR(0) canonical parsers, LALR(1) parsers, LR(1) canonical parsers, and my split node parsers.

-- a graph is a collection of nodes and arcs

Graph: TYPE = REF GraphBody;
GraphBody: TYPE;

Node: TYPE = REF NodeBody;
NodeBody: TYPE;

GraphClass: TYPE = {LR0, LALR1, SplitNode};


-- operations on graphs as a whole

CreateEmptyGraph: PROC[Grammar, GraphClass] RETURNS[Graph];

GetGraphStats: PROC[Graph] RETURNS[nNodes, nArcs, nNodesMarkedToSplit: INT];


GetClass: PROC[Graph] RETURNS[GraphClass];

GetGrammar: PROC[Graph] RETURNS[Grammar];

GetStartNode: PROC[Graph] RETURNS[Node];

GetAnyStage1Node: PROC[Graph] RETURNS[Node];

GetAnyDirtyNode: PROC[Graph] RETURNS[Node];

GenerateAllNodes: PROC[Graph, PROC[Node] RETURNS[--continue--BOOLEAN]];

ClearAllUpperNodePointers: PROC[Graph];

IndexTheNodes: PROC[Graph]; -- can only be done once

CleanTheGraph: PROCEDURE[graph: Graph] RETURNS[Graph]; -- so that it can be garbage collected (returns NIL)



-- operations on nodes

CreateTentativeStage1Node: PROC[g: Graph, s: REF ANY, base: Node] RETURNS[Node]; 

InstallStage1Node: PROC[n: Node, startNode: BOOLEAN];

SetUpperNode: PROC[n: Node, upper: Node];

SetRingNumber: PROC[n: Node, ring: CARDINAL];

AppendAnArc: PROC[source: Node, s: Symbol, target: Node];

ResetArcTarget: PROC[source: Node, s: Symbol, newTarget: Node];

SetAssociatedSet: PROC[Node, --new value-- REF ANY, --old value-- REF ANY]; -- S

MarkAsStage2: PROC[Node];

MarkNodeDirty: PROC[Node];

MarkNodeToSplit: PROC[Node];





GetGraph: PROC[Node] RETURNS[Graph];

GenerateArcs: PROC[Node, PROC[Symbol, Node] RETURNS[--continue-- BOOLEAN]];

FollowSymbol: PROC[Node, Symbol] RETURNS[Node];

GetAssociatedSet: PROC[Node] RETURNS[REF ANY]; -- S

GetBaseNode: PROC[Node] RETURNS[Node]; -- upsilon

GetUpperNode: PROC[Node] RETURNS[Node]; -- psi

GetRingNumber: PROC[Node] RETURNS[CARDINAL];

GetSplittingMark: PROC[Node] RETURNS[BOOLEAN];

NarrowNode: PROC[REF ANY] RETURNS[Node];

GetNodeIndex: PROC[Node] RETURNS[CARDINAL];


 
END..