summaryrefslogtreecommitdiffstats
path: root/eshtrans/backend/codegen.esh
blob: 9e95956662cf254fe0d24b6a773fa04f5df4399d (plain)
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
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
# Shell command language code generator
#
# Copyright (C) 2016  Patrick "P. J." McDermott
#
# This file is part of the Eggshell Compiler.
#
# The Eggshell Compiler is free software: you can redistribute it
# and/or modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation, either version 3 of
# the License, or (at your option) any later version.
#
# The Eggshell Compiler is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied warranty
# of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with the Eggshell Compiler.  If not, see
# <http://www.gnu.org/licenses/>.

sbufi=
sbufc=
sc=
tu_id=
static_fn_n=

sgetc()
{
	if [ ${sbufi} -ge ${sbufc} ]; then
		sc=''
	else
		eval "sc=\${sbufv_${sbufi}}"
		sbufi=$((${sbufi} + 1))
	fi
}

add_static_fn()
{
	local fn="${1}"

	printf '__%s_static_fns="${__%s_static_fns} %s:__%s_fn%d"\n' \
		"${tu_id}" "${tu_id}" "${fn}" "${tu_id}" ${static_fn_n}
	printf '__%s_fn%d' "${tu_id}" ${static_fn_n}
	static_fn_n=$((${static_fn_n} + 1))
}

codegen_sub()
{
	local array="${1}"
	shift 1
	local print_spc=
	local ionum=
	local fname=
	local static=
	local static_fname=

	print_spc=false
	ionum=false
	fname=''
	static=false
	static_fname=false

	IFS="${RS}"
	for t in ${array}; do
		if ${print_spc}; then
			case "${t%${US}*}" in
				T_NEWLINE)
					;;
				*)
				printf ' '
					;;
			esac
			print_spc=false
		fi

		# Handle I/O number false positives.
		if ${ionum}; then
			case "${t%${US}*}" in
				T_WORD|T_CMDNAME|T_FNAME)
					printf ' '
				;;
			esac
			ionum=false
		fi

		# Function names
		case "${t%${US}*}" in T_FNAME)
			fname="${t}"
			;;
		esac

		# State machine for static variables and functions
		case "${t%${US}*}" in
			T_STATIC)
				static=true
				continue
				;;
		esac
		if ${static}; then
			static=false
			case "${t%${US}*}" in
				T_FNAME)
					static_fname=true
					continue
					;;
				*)
					toktext T_STATIC
					printf ' '
					;;
			esac
		elif ${static_fname}; then
			static_fname=false
			case "${t%${US}*}" in
				T_LPAREN)
					add_static_fn "${fname#*${US}}"
					;;
				*)
					toktext T_STATIC
					printf ' '
					toktext "${fname}"
					;;
			esac
		fi

		# Function start/end tokens
		case "${t%${US}*}" in
			T_FN_START)
				printf '__fn_start %s %s;' \
					"${tu_id}" "${fname#*${US}}"
				;;
			T_FN_END)
				printf '__fn_end;'
				;;
			T_RETURN)
				printf '__fn_end; '
				;;
		esac

		toktext "${t}"

		case "${t%${US}*}" in
			T_NEWLINE|T_LPAREN)
				# Indenting lines can mess up here-documents.
				# Adding a space after "(" can mess up function
				# definitions (on zsh at least, while other
				# shells accept the space).
				;;
			T_IO_NUMBER)
				ionum=true
				;;
			*)
				print_spc=true
				;;
		esac
	done
	unset IFS
}

# The token stack is encoded in a string in the following grammar:
#     Terminal symbols:
#         TOKEN
#     Production rules:
#         stack  = tokens [ '<SOH>' type '<STX>' stack '<ETX>' [ tokens ] ] ;
#         tokens = TOKEN { '<RS>' TOKEN } ;
#         type   = 'C' ;
# We need to recurse through this stack to get to all the tokens.
# Each element in the stack (an array of tokens) gets run through the codegen to
# become text that is inserted into the array below.
parse_stack()
{
	local array=
	local res=

	array=''
	while :; do
		sgetc
		case "${sc}" in
			'')
				# EOF
				break
				;;
			"${SOH}")
				# New stack element
				sgetc
				case "${sc}" in
					'C')
						# Command substitution
						sgetc  # STX
						res="$(parse_stack)"
						sbufi="${res%% *}"
						array="${array}${res#* }"
						;;
				esac
				;;
			"${ETX}")
				# End of stack element
				break
				;;
			*)
				# Token character
				array="${array}${sc}"
				;;
		esac
	done
	printf '%d ' ${sbufi}
	codegen_sub "${array}"
}

sh_parse_stack()
{
	local buf="${1}"
	shift 1
	local res=

	eval "$(printf '%s' "${buf}" | awk -v FS='' -v j=0 \
		-v squote="'" -v esc_squote="'\\\\''" '
		{
			for (i = 1; i <= NF; ++i) {
				sub(squote, esc_squote, $i);
				printf("sbufv_%d='\''%s'\''\n", j++, $i);
			};
			printf("sbufv_%d='\''\n'\''\n", j++);
		}
		')"
	sbufi=0
	sbufc=${#buf}
	res="$(parse_stack; printf '.')"
	res="${res%.}"
	printf '%s' "${res#* }"
}

sh_set_tu_id()
{
	local toks="${1}"

	tu_id="$(printf '%s' "${toks}" | sha256sum -)"
	tu_id="${tu_id%  -}"

	return 0
}

sh_start_tu()
{
	printf '__tu=%s\n' "${tu_id}"
	printf '__%s_static_vars=\n' "${tu_id}"
	printf '__%s_static_var_vals=\n' "${tu_id}"
	printf '__%s_static_fns=\n' "${tu_id}"
	static_fn_n=0
}

sh_end_tu()
{
	printf '__tu_end\n'
}