context management
NextLevel: PROC[ContextLevel] RETURNS[ContextLevel];
CtxLevel: PROC[CTXIndex] RETURNS[ContextLevel];
SetCtxLevel: PROC[CTXIndex, ContextLevel];
BlockLevel: PROC[ContextLevel] RETURNS[ContextLevel];
NewCtx: PROC[ContextLevel] RETURNS[CTXIndex];
SetMainCtx: PROC[CTXIndex];
ResetCtxList: PROC[CTXIndex];
FirstVisibleSe: PROC[CTXIndex] RETURNS[ISEIndex];
NextVisibleSe: PROC[ISEIndex] RETURNS[ISEIndex];
VisibleCtxEntries: PROC[CTXIndex] RETURNS[CARDINAL];
CtxVariant: PROC[CTXIndex] RETURNS[ISEIndex];
StaticNestError: SIGNAL;
MakeCtxSe: PROC[name: Name, ctx: CTXIndex] RETURNS[ISEIndex];
MakeNonCtxSe: PROC[CARDINAL] RETURNS[CSEIndex];
MakeSeChain: PROC[CTXIndex, CARDINAL, BOOL] RETURNS[ISEIndex];
FillCtxSe: PROC[ISEIndex, Name, BOOL];
NameClash: SIGNAL [name: Name];
EnterExtension: PROC[sei: ISEIndex, type: ExtensionType, tree: Tree.Link];
SetSeLink: PROC[sei, next: ISEIndex];
copying within current table
CopyArgSe: PROC[copy, master: ISEIndex];
CopyBasicType: PROC[CSEIndex] RETURNS[CSEIndex];
CopyXferType: PROC[CSEIndex, Tree.Map] RETURNS[CSEIndex];