On 11/11/2022 10:53 AM, Max Chernoff via ntg-context wrote:
Hi,
I want to simulate \hss in lua end in ConTeXt/luametatex environment.
For example,
```ConTeXt
a{\raise 1.5ex\hbox to 0pt{\hss b}}c
```
And in lua, I do as follows(part of my app seen in attachment):
Your code doesn't compile as is. I think that this is the same thing
though:
\starttext
\startluacode
local a = node.new"glyph"
a.char = string.byte("a")
a.font = font.current()
local b = node.new"glyph"
b.char = string.byte("b")
b.font = font.current()
local c = node.new"glyph"
c.char = string.byte("c")
c.font = font.current()
local hss = node.new("glue")
hss.stretch = 65536
hss.stretchorder = 2
hss.shrink = 65536
hss.shrinkorder = 2
hss.width = 0
b = node.insertbefore(b, b, hss)
local box = node.new("hlist", "box")
box.head = b
box.width = 0
box.shift = -tex.sp("1ex")
tex.forcehmode()
node.write(a + box + c)
\stopluacode
\stoptext
And got 'b' on top of 'c' in pdf as follows:
```pdf
b
ac
```
The \hss isn't the problem here. The problem is actually with the box.
When you manually make the \hbox like that, I think (although I could be
wrong) that you're bypassing all of TeX's glue calculations. You should
probably use "node.hpack" instead:
\starttext
\startluacode
local a = node.new"glyph"
a.char = string.byte("a")
a.font = font.current()
local b = node.new"glyph"
b.char = string.byte("b")
b.font = font.current()
local c = node.new"glyph"
c.char = string.byte("c")
c.font = font.current()
local hss = node.new("glue")
hss.stretch = 65536
hss.stretchorder = 2
hss.shrink = 65536
hss.shrinkorder = 2
hss.width = 0
local box = node.hpack(hss + b, "exactly", 0)
box.shift = -tex.sp("1ex")
tex.forcehmode()
a.next = box
box.next = c
node.write(a)
\stopluacode
\stoptext
indeed, an dafter that you can check it
box.glueorder : 2
box.glueset : 6.6683349609375
box.gluesign : 2
which will be applied (in the backend) to glues
Hans
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