1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
|
#############################################################################
##
#W pager.gi GAP Library Frank Lbeck
##
#H @(#)$Id: pager.gi,v 1.4 2002/05/10 12:56:28 gap Exp $
##
#Y Copyright (C) 2001, Lehrstuhl D fuer Mathematik, RWTH Aachen, Germany
#Y (C) 2001 School Math and Comp. Sci., University of St. Andrews, Scotland
#Y Copyright (C) 2002 The GAP Group
##
## The files pager.g{d,i} contain the `Pager' utility. A rudimentary
## version of this was integrated in first versions of GAP's help system.
## But this utility is certainly useful for other purposes as well.
##
Revision.pager_gi :=
"@(#)$Id: pager.gi,v 1.4 2002/05/10 12:56:28 gap Exp $";
##
## There is a builtin pager `PAGER_BUILTIN', but at least under UNIX one
## should use an external one. This can be set via the variable `PAGER'
## (e.g., PAGER := "less";). Here, `less' should be in the executable
## PATH of the user and we assume that it supports an argument `+num' for
## starting display in line number `num'. Additional options can be
## assigned to `PAGER_OPTIONS' as list of strings.
##
## The user function is `Pager'.
##
## The input of `Pager( lines )' can have one the following forms:
##
## (1) a string (i.e., lines are separated by '\n')
## (2) a list of strings (without '\n') interpreted as lines of output
## (3) a record with component .lines as in (1) or (2) and optional further
## components
##
## In (3) currently the following components are used:
##
## .formatted (true/false) If true, the builtin pager tries to avoid
## line breaks by GAP's Print.
## .start (number) The display is started with line .start, but
## beginning is available via back scrolling
##
#############################################################################
##
#F PAGER_BUILTIN( <lines> ) . . . . . . . . . . . . . . . . format lines
##
# We take into account a variable from the GAPDoc package. If the text
# contains ANSI color sequences we reset the terminal before we print the
# last line.
if not IsBound(ANSI_COLORS) then
ANSI_COLORS := false;
fi;
BindGlobal("PAGER_BUILTIN", function( lines )
local formatted, linepos, size, wd, pl, count, i, stream,
halt, delhaltline, from, len, char, out;
formatted := false;
linepos := 1;
# don't print this to LOG files
out := OutputTextUser();
if IsRecord(lines) then
if IsBound(lines.formatted) then
formatted := lines.formatted;
fi;
if IsBound(lines.start) then
linepos := lines.start;
fi;
lines := lines.lines;
fi;
if IsString(lines) then
lines := SplitString(lines, "\n", "");
fi;
size := SizeScreen();
wd := QuoInt(size[1]+2, 2);
# really print line without breaking it
pl := function(l)
local r;
r := 1;
while r*wd<=Length(l) do
PrintTo(out, l{[(r-1)*wd+1..r*wd]}, "\c");
r := r+1;
od;
if (r-1)*wd < Length(l) then
PrintTo(out, l{[(r-1)*wd+1..Length(l)]});
fi;
PrintTo(out, "\n");
end;
if not formatted then
# cope with overfull lines
count:=1;
while count<=Length(lines) do
if Length(lines[count])>size[1]-2 then
# find the last blank before this position
i:=size[1]-2;
while i>0 and lines[count][i]<>' ' do
i:=i-1;
od;
if i>0 then
if not IsBound(lines[count+1]) then
lines[count+1]:="";
fi;
lines[count+1]:=Concatenation(
lines[count]{[i+1..Length(lines[count])]}," ", lines[count+1]);
lines[count]:=lines[count]{[1..i-1]};
fi;
fi;
count:=count+1;
od;
fi;
stream := InputTextFile("*errin*");
count := 0;
halt :=
" -- <space> page, <n> next line, <b> back, <p> back line, <q> quit --\c";
if IsBound(ANSI_COLORS) and ANSI_COLORS = true then
halt := Concatenation("\033[0m", halt);
fi;
delhaltline := function()
local i;
for i in halt do
if i <> '\c' then
PrintTo(out, "\b\c \c\b\c" );
fi;
od;
end;
from := linepos;
len := Length(lines);
repeat
for i in [from..Minimum(len, from+size[2]-2)] do
pl(lines[i]);
od;
if len = i+1 then
pl(lines[len]);
char := 'q';
elif len = i then
char := 'q';
else
PrintTo(out, halt);
char := CHAR_INT(ReadByte(stream));
while not char in " nbpq" do
char := CHAR_INT(ReadByte(stream));
od;
if char = ' ' then
from := from+size[2]-1;
elif char = 'n' then
from := from+1;
elif char = 'p' and from>1 then
from := from-1;
elif char = 'b' then
from := Maximum(1, from-size[2]+1);
fi;
delhaltline();
fi;
until char = 'q';
CloseStream(stream);
end);
# for using `more' or `less' or ... (read from `PAGER')
# we assume that PAGER allows command line option +num for starting
# display in line num
PAGER := "builtin";
PAGER_OPTIONS := [];
BindGlobal("PAGER_EXTERNAL", function( lines )
local path, pager, linepos, str, i, cmdargs, stream;
path := DirectoriesSystemPrograms();
pager := Filename(path, PAGER);
if pager=fail then
Error("Pager ", PAGER, " not found, change `PAGER'.");
fi;
linepos := 1;
if IsRecord(lines) then
if IsBound(lines.start) then
linepos := lines.start;
fi;
lines := lines.lines;
fi;
if not IsString(lines) then
str:="";
for i in lines do
Append(str,i);
Add(str,'\n');
od;
lines := str;
fi;
if linepos > 1 then
cmdargs := [Concatenation("+", String(linepos))];
else
cmdargs := [];
fi;
stream:=InputTextString(lines);
Process(path[1], pager, stream, OutputTextUser(),
Concatenation(PAGER_OPTIONS, cmdargs));
end);
InstallGlobalFunction("Pager", function(lines)
if PAGER="builtin" then
PAGER_BUILTIN(lines);
else
PAGER_EXTERNAL(lines);
fi;
end);
|
