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
|
(* This is an example how to use the new syntactic elements: *)
(**********************************************************************)
(* interpolate *)
(**********************************************************************)
(* interpolate "string":
* In the string literal brace expansion is performed. The following
* notations are allowed:
* $name expands to the value of the string variable 'name'
* $Module.name expands to the value of the string variable 'name'
* of 'Module'
* ${name} same as $name
* ${Module.name} same as $Module.name
* ${name,%format} expands to the value of the variable 'name' which
* has been converted to a string using "%format".
* The format string may be anything allowed in printf.
* ${Module.name,%format} works,too
* \$ A dollar character
* \<newline> Expands to the empty string
* All backslash sequences of normal string constants are allowed, too.
*
* NOTE: For non-string variables a format specification is required;
* otherwise type checking is impossible.
*)
let s = "The number" in
let f = 3.14 in
let i = 42 in
print_string interpolate "$s ${f,%f} is not ${i,%d}\n";;
(**********************************************************************)
(* interpolate file *)
(**********************************************************************)
(* interpolate file "filename":
* expands to the contents of the file; brace expansion is performed
* (see above).
* If "filename" is written without "/", it is always searched in the
* same directory as the source file being compiled. Otherwise "filename"
* is interpreted as relative or absolute path name.
*
* IMPORTANT NOTE: Of course, the file is only read during compile time.
*)
let s = "The number" in
let f = 3.14 in
let i = 42 in
print_string interpolate file "sample.file";;
(**********************************************************************)
(* include_file *)
(**********************************************************************)
(* include_file "filename":
* expands to the contents of the file but _no_ brace expansion is performed.
* If "filename" is written without "/", it is always searched in the
* same directory as the source file being compiled. Otherwise "filename"
* is interpreted as relative or absolute path name.
*
* IMPORTANT NOTE: Of course, the file is only read during compile time.
*
* Note: Up to xstrp4-1.4, this construction used the notation
* "include file". In xstrp4-1.5, it was changed to "include_file"
* to avoid ambiguities with O'Caml's built-in "include" directive.
*)
print_string "sample.file: ";
print_string include_file "sample.file";;
(**********************************************************************)
(* <:here< quotations>> *)
(**********************************************************************)
(* It is also possible to use the 'here' quotation which does brace
* expansion on its argument. This is sometimes easier to write because
* the double quotes need no escaping. Of course, $ and \ characters
* must still be escaped.
* Only \$, \<newline>, \>, and \\ are allowed as backslash sequences.
*)
let s = "The number" in
let f = 3.14 in
let i = 42 in
print_string <:here<\
The interpolation example was:
print_string interpolate "\$s \${f,%f} is not \${i,%d}\n";;
-- where s was replaced by "$s", f by "${f,%f}", and i by "${i,%d}".
>>
(**********************************************************************)
(* Access to record fields *)
(**********************************************************************)
(* It is also possible to access record fields. Just use the standard
* OCaml notation rcrd.field.
*)
type rcrd =
{
s: string;
f: float;
i: int;
}
let rcrd = {s = "The number"; f = 3.14; i = 42} in
print_string interpolate "$rcrd.s ${rcrd.f,%f} is not ${rcrd.i,%d}\n";;
|
