6.8 Anchor-hanger binding functions

Because functions from the d-hierarchy are sometimes awkward to use, there is another set of functions which can be used to obtain similar results. Most of the consequent functions are clear if you know that:

• The connection between GOs, hangers and anchors looks like this:
  go1 – hanger – anchor – go2,
• a go is joined to a set of hangers (each identified with a term),
• a go is joined to a set of anchors (each identified with a term),
• a hanger is joined to exactly one go and set of anchors (without identification, ordered arbitrarily)
• an anchor is joined to exactly one go and exactly one hanger,
• anchor siblings are anchors hanging on the same hanger.

(go-hanger g id)
go symbol -> hanger

(go-hangers g)
go -> list

(go-anchor g id)
go symbol -> anchor

(go-anchors g)
go -> list

(anchor-first-sib a)
anchor -> anchor

(anchor-last-sib a)
anchor -> anchor

(anchor-next-sib a)
anchor -> anchor

(anchor-prev-sib a)
anchor -> anchor

(anchor-hanger a)
anchor -> hanger

(anchor-go a)
anchor -> go

(hanger-first-anchor h)
hanger -> anchor

(hanger-last-anchor h)
hanger -> anchor

(hanger-anchors h)
hanger -> list

(hanger-go h)
hanger -> go

(h-HANGER g)
go -> hanger

Returns the appropriate hanger of GO g. It is a shorthand for calling go-hanger. For example, (h-start go) is equivalent to (go-hanger go 'start).

(a-ANCHOR g)
go -> anchor

Returns the appropriate anchor of GO g. It is a shorthand for calling go-anchor. For example, (a-start go) is equivalent to (go-anchor go 'start).

(i-HANGER g)
go -> hanger

Returns the hanger on which the appropriate anchor of GO g is hanging. It is a shorthand for calling go-anchor and anchor-hanger. For example, (i-start go) is equivalent to (anchor-hanger (go-anchor go 'start)). i- means input.

(anchor-set-hanger! a h)
anchor hanger -> unspecified
Changes the anchor a to hang on hanger h. This function must be called in an appropriate transaction.

(set-i-ANCHOR! g h)
go hanger -> unspecified

Changes the appropriate anchor of GO g to hang on hanger h. It is a shorthand for calling go-anchor and anchor-set-hanger!. For example, (set-i-start! go h) is equivalent to (anchor-set-hanger! (go-anchor go 'start) h). i- means input. The function must be called in an appropriate transaction.

(anchor-term a)
anchor -> symbol
Returns the term for anchor a (identifying that anchor in the corresponding go).

(hanger-term h)
hanger -> symbol
Returns the term for hanger h (identifying that hanger in the corresponding go).