@x
@d normal=0 {the most common case when several cases are named}
@y
@d normal=0 {the most common case when several cases are named}
@d under_accent=2 {|subtype| of under math accents}
@d nesting=1 {add this to an accent |subtype| to make it nesting}
@z
@x
math_accent: print_esc("mathaccent");
@y
math_accent: case chr_code of
normal: print_esc("mathaccent");
normal+nesting: print_esc("nestingmathaccent");
under_accent: print_esc("mathunderaccent");
under_accent+nesting:print_esc("nestingmathunderaccent");
othercases print("Unknown accent!")
endcases;
@z
@x
accent_noad: make_math_accent(q);
@y
accent_noad: if subtype(q)<under_accent then make_math_accent(q)
else make_math_under_accent(q);
@z
@x
procedure make_math_accent(@!q:pointer);
label done,done1;
var p,@!x,@!y:pointer; {temporary registers for box construction}
@y
procedure horizontally_stack_into_box(@!b:pointer;@!f:internal_font_number;@!c:quarterword);
var p:pointer; {new node placed into |b|}
begin
p:=char_box(f,c); link(p):=list_ptr(b); list_ptr(b):=p;
width(b):=width(b)+width(p);
end;
procedure make_math_under_accent(@!q:pointer);
label done,done1,done2,done3;
var p,qq,@!x,@!y:pointer; {temporary registers for box construction}
@!a:integer; {address of lig/kern instruction}
@!c:quarterword; {accent character}
@!f:internal_font_number; {its font}
@!i,ii:four_quarters; {its |char_info|}
@!s:scaled; {amount to skew the accent to the right}
@!h:scaled; {height of character being accented}
@!delta,sep:scaled; {space to insert between accentee and accent}
@!w,v,u:scaled; {width of the accentee, not including sub/superscripts}
@!t:four_quarters;
@!m,n:integer;
@!hd:eight_bits;
begin fetch(accent_chr(q));
if char_exists(cur_i) then
begin i:=cur_i; c:=cur_c; f:=cur_f;@/
@<Compute under accent skew@>;
@<Compute separation for under accent@>;
x:=clean_box(nucleus(q),cur_style); w:=width(x); h:=height(x);
@<Switch to a larger accent if available and appropriate@>;
if (math_type(supscr(q))<>empty)or(math_type(subscr(q))<>empty) then
if math_type(nucleus(q))=math_char then
@<Swap the subscript and superscript into box |x|@>;
shift_amount(y):=half(w-width(y))-s; width(y):=0;
p:=new_kern(sep); link(x):=p; link(p):=y;
p:=new_kern(-sep-x_height(f)); link(y):=p;
y:=vpack(x,natural); width(y):=w;
depth(y):=depth(y)+height(y)-h; height(y):=h;
info(nucleus(q)):=y; math_type(nucleus(q)):=sub_box;
end;
end;
procedure make_math_accent(@!q:pointer);
label done,done1,done2;
var p,qq,@!x,@!y:pointer; {temporary registers for box construction}
@z
@x
@!w:scaled; {width of the accentee, not including sub/superscripts}
@y
@!w,v,u:scaled; {width of the accentee, not including sub/superscripts}
@!t:four_quarters;
@!m,n:integer;
@!hd:eight_bits;
@z
@x
y:=char_box(f,c);
@y
@z
@x
@ @<Switch to a larger accent if available and appropriate@>=
loop@+ begin if char_tag(i)<>list_tag then goto done;
y:=rem_byte(i);
i:=char_info(f)(y);
if not char_exists(i) then goto done;
if char_width(f)(i)>w then goto done;
c:=y;
end;
done:
@y
@ @<Switch to a larger accent if available and appropriate@>=
loop@+ begin
if char_tag(i)=ext_tag then begin
y:=new_null_box;
type(y):=hlist_node;
i:=font_info[exten_base[f]+rem_byte(i)].qqqq;@/
c:=ext_rep(i); t:=char_info(f)(c); u:=char_width(f)(t); v:=0;
hd:=height_depth(t); height(y):=char_height(f)(hd); depth(y):=char_depth(f)(hd);
c:=ext_bot(i); t:=char_info(f)(c); @+if c<>min_quarterword then v:=v+char_width(f)(t);
c:=ext_mid(i); t:=char_info(f)(c); @+if c<>min_quarterword then v:=v+char_width(f)(t);
c:=ext_top(i); t:=char_info(f)(c); @+if c<>min_quarterword then v:=v+char_width(f)(t);
n:=0;
if u>0 then while v<w do begin
v:=v+u; incr(n);
if ext_mid(i)<>min_quarterword then v:=v+u;
end;
c:=ext_bot(i);
if c<>min_quarterword then horizontally_stack_into_box(y,f,c);
c:=ext_rep(i);
for m:=1 to n do horizontally_stack_into_box(y,f,c);
c:=ext_mid(i);
if c<>min_quarterword then begin
horizontally_stack_into_box(y,f,c);
c:=ext_rep(i);
for m:=1 to n do horizontally_stack_into_box(y,f,c);
end;
c:=ext_top(i);
if c<>min_quarterword then horizontally_stack_into_box(y,f,c);
goto done2;
end;
if char_tag(i)<>list_tag then goto done;
y:=rem_byte(i);
i:=char_info(f)(y);
if not char_exists(i) then goto done;
if char_width(f)(i)>w then goto done;
c:=y;
end;
done:
y:=char_box(f,c);
done2:
@z
%
% Here is the logic for finding the accentee:
% We pass by accent_noads as long as they are of the opposite kind
% or of same kind and also nesting. This logic is necessary to make
% \Hat{\uhat{\hat A}} align the two hats properly.
@x
@ @<Compute the amount of skew@>=
s:=0;
if math_type(nucleus(q))=math_char then
begin fetch(nucleus(q));
@y
@ @<Compute under accent skew@>=
s:=0;
qq:=q;
if odd(subtype(q)) then
while (math_type(nucleus(qq))=sub_mlist)and
(type(info(nucleus(qq)))=accent_noad)and
((subtype(qq)=subtype(q))or(subtype(qq) div 2<>subtype(q) div 2)) do
qq:=info(nucleus(qq));
if math_type(nucleus(qq))=math_char then
begin fetch(nucleus(qq));
ii:=char_info(cur_f)(skew_char[cur_f]);
if char_tag(ii)=lig_tag then
begin a:=lig_kern_start(cur_f)(ii);
ii:=font_info[a].qqqq;
if skip_byte(ii)>stop_flag then
begin a:=lig_kern_restart(cur_f)(ii);
ii:=font_info[a].qqqq;
end;
loop@+ begin if qo(next_char(ii))=cur_c then
begin if op_byte(ii)>=kern_flag then
if skip_byte(ii)<=stop_flag then s:=char_kern(cur_f)(ii);
goto done1;
end;
if skip_byte(ii)>=stop_flag then goto done1;
a:=a+qo(skip_byte(ii))+1;
ii:=font_info[a].qqqq;
end;
end;
end;
done1:
@ @<Compute separation for under accent@>=
sep:=0;
ii:=i;
if char_tag(ii)=lig_tag then
begin a:=lig_kern_start(f)(ii);
ii:=font_info[a].qqqq;
if skip_byte(ii)>stop_flag then
begin a:=lig_kern_restart(f)(ii);
ii:=font_info[a].qqqq;
end;
loop@+ begin if qo(next_char(ii))=c then
begin if op_byte(ii)>=kern_flag then
if skip_byte(ii)<=stop_flag then sep:=char_kern(f)(ii);
goto done3;
end;
if skip_byte(ii)>=stop_flag then goto done3;
a:=a+qo(skip_byte(ii))+1;
ii:=font_info[a].qqqq;
end;
end;
done3:
@ @<Compute the amount of skew@>=
s:=0;
qq:=q;
{while odd(subtype(qq))and(math_type(nucleus(qq))=sub_mlist)and
(type(info(nucleus(qq)))=accent_noad) do}
if odd(subtype(q)) then
while (math_type(nucleus(qq))=sub_mlist)and
(type(info(nucleus(qq)))=accent_noad)and
((subtype(qq)=subtype(q))or(subtype(qq) div 2<>subtype(q) div 2)) do
qq:=info(nucleus(qq));
if math_type(nucleus(qq))=math_char then
begin fetch(nucleus(qq));
@z
@x
procedure math_ac;
begin if cur_cmd=accent then
@<Complain that the user should have said \.{\\mathaccent}@>;
tail_append(get_node(accent_noad_size));
type(tail):=accent_noad; subtype(tail):=normal;
@y
procedure math_ac;
begin if cur_cmd=accent then
@<Complain that the user should have said \.{\\mathaccent}@>;
tail_append(get_node(accent_noad_size));
type(tail):=accent_noad; subtype(tail):=cur_chr;
@z
