1	#!/usr/bin/env bash
2	#
3	# Test call stack introspection. There are a bunch of special variables
4	# defined here:
5	#
6	# https://www.gnu.org/software/bash/manual/html_node/Bash-Variables.html
7	#
8	# - The shell function ${FUNCNAME[$i]} is defined in the file
9	# ${BASH_SOURCE[$i]} and called from ${BASH_SOURCE[$i+1]}
10	#
11	# - ${BASH_LINENO[$i]} is the line number in the source file
12	# (${BASH_SOURCE[$i+1]}) where ${FUNCNAME[$i]} was called (or
13	# ${BASH_LINENO[$i-1]} if referenced within another shell function).
14	#
15	# - For instance, ${FUNCNAME[$i]} was called from the file
16	# ${BASH_SOURCE[$i+1]} at line number ${BASH_LINENO[$i]}. The caller builtin
17	# displays the current call stack using this information.
18	#
19	# So ${BASH_SOURCE[@]} doesn't line up with ${BASH_LINENO}. But
20	# ${BASH_SOURCE[0]} does line up with $LINENO!
21	#
22	# Geez.
23
24
25	### ${FUNCNAME[@]} array
26	g() {
27	argv.py "${FUNCNAME[@]}"
28	}
29	f() {
30	argv.py "${FUNCNAME[@]}"
31	g
32	argv.py "${FUNCNAME[@]}"
33	}
34	f
35	## STDOUT:
36	['f']
37	['g', 'f']
38	['f']
39	## END
40
41	### ${BASH_SOURCE[@]} is a stack of source files for function calls
42	$SH spec/testdata/bash-source.sh
43	## STDOUT:
44	['begin F funcs', 'f', 'main']
45	['begin F files', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
46	['begin F lines', '21', '0']
47	['G funcs', 'g', 'f', 'main']
48	['G files', 'spec/testdata/bash-source-2.sh', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
49	['G lines', '15', '21', '0']
50	['end F funcs', 'f', 'main']
51	['end F', 'spec/testdata/bash-source.sh', 'spec/testdata/bash-source.sh']
52	['end F lines', '21', '0']
53	## END
54
55	### ${BASH_LINENO[@]} is a stack of line numbers for function calls
56	# note: it's CALLS, not DEFINITIONS.
57	g() {
58	argv.py G "${BASH_LINENO[@]}"
59	}
60	f() {
61	argv.py 'begin F' "${BASH_LINENO[@]}"
62	g # line 6
63	argv.py 'end F' "${BASH_LINENO[@]}"
64	}
65	f # line 9
66	## STDOUT:
67	['begin F', '9']
68	['G', '6', '9']
69	['end F', '9']
70	## END
71
72	### $LINENO is the current line, not line of function call
73	g() {
74	argv.py $LINENO # line 2
75	}
76	f() {
77	argv.py $LINENO # line 5
78	g
79	argv.py $LINENO # line 7
80	}
81	f
82	## STDOUT:
83	['5']
84	['2']
85	['7']
86	## END