[luatex] how to assign a width to a node of type "glue"

[Paul Isambert]

Mico Loretan <mico.loretan at mac.com> a écrit:
> I'm trying to create a glue node that has a specific width. Unfortunately, I seem to be missing something (probably entirely trivial to somebody who knows how it's done).
> 
> Here's what I've tried so far:
> 
> local glue        = node.id ( "glue" )       -- 10
> local gluespec    = node.id ( "glue_spec" )  -- 47
> local gluenode    = node.new ( glue )        -- create the node
> gluenode.subtype  = 0                        -- "skip"
> -- what next??
> 
> I would like to make this node have a width of 0.03em (no stretchability or shrinkability needed).
> 
> The LuaTeX reference manual (p. 178) says that I should do something with the node's field called "gluenode.spec". If I understand the manual correctly, this field should be a "pointer to an item of type 'glue_spec'." However, there's no indication on how this should be done, and the explanation of glue_spec on pp. 173f. is even terser.

A glue node points to a glue_spec node that contains the real stuff; I
*think* that that akward interface will disappear one day and glue
nodes will contain their own information. Meanwhile:

    local gluenode = node.new(node.id("glue"))
    local gluespec = node.new(node.id("glue_spec"))

    gluespec.width = tex.sp("0.03em")
    gluenode.spec = gluespec

Best,
Paul