1 /*
2  * Copyright (c) 2021 Omar Polo <op@omarpolo.com>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #ifndef SCRIPT_H
18 #define SCRIPT_H
19 
20 enum {
21 	/* literals */
22 	V_SYM,
23 	V_STR,
24 	V_NUM,
25 
26 	/* foreign */
27 	V_MSG,
28 	V_QIDVEC,
29 	V_QID,
30 
31 	/* casted */
32 	V_U8,
33 	V_U16,
34 	V_U32,
35 };
36 
37 struct value {
38 	int type;
39 	union {
40 		char		*str;
41 		int64_t		 num;
42 		uint8_t		 u8;
43 		uint16_t	 u16;
44 		uint32_t	 u32;
45 		struct {
46 			uint8_t	*msg;
47 			size_t	 len;
48 		} msg;
49 		struct {
50 			uint8_t	*start;
51 			size_t	 len;
52 		} qidvec;
53 		uint8_t		 qid[QIDSIZE];
54 	} v;
55 };
56 
57 enum {
58 	OP_REST,
59 	OP_ASSIGN,
60 	OP_ASSERT,
61 	OP_FUNCALL,
62 	OP_LITERAL,
63 	OP_VAR,
64 	OP_CAST,
65 	OP_CMP_EQ,
66 	OP_CMP_LEQ,
67 	OP_FACCESS,
68 	OP_SFAIL,
69 	OP_VARGS,
70 };
71 
72 struct proc;
73 
74 struct op {
75 	struct op	*next;
76 	int		 type;
77 	union {
78 		struct {
79 			char		*name;
80 			struct op	*expr;
81 		} assign;
82 		struct op		*assert;
83 		struct {
84 			struct proc	*proc;
85 			struct op	*argv;
86 			int		 argc;
87 		} funcall;
88 		struct value literal;
89 		char *var;
90 		struct {
91 			struct op	*expr;
92 			int		 totype;
93 		} cast;
94 		struct {
95 			struct op	*a;
96 			struct op	*b;
97 		} bin_cmp;
98 		struct {
99 			struct op	*expr;
100 			char		*field;
101 		} faccess;
102 		struct {
103 			char		*msg;
104 			struct op	*expr;
105 		} sfail;
106 	} v;
107 };
108 
109 TAILQ_HEAD(bindings, binding);
110 struct binding {
111 	TAILQ_ENTRY(binding)	 entry;
112 	char			*name;
113 	struct value		 val;
114 
115 	/*
116 	 * Hack to support varargs.  We set a special variable named
117 	 * "..." that contains the list of ops that will evaluate to
118 	 * the arguments.
119 	 */
120 	struct op		*raw;
121 };
122 
123 TAILQ_HEAD(envs, env);
124 struct env {
125 	TAILQ_ENTRY(env)	 entry;
126 	struct bindings		 bindings;
127 };
128 
129 TAILQ_HEAD(opstacks, opstack);
130 struct opstack {
131 	TAILQ_ENTRY(opstack)	 entry;
132 	struct op		 base;
133 	struct op		*last;
134 	int			 counter;
135 };
136 
137 TAILQ_HEAD(procs, proc);
138 struct proc {
139 	TAILQ_ENTRY(proc)	 entry;
140 	char			*name;
141 	int			 minargs;
142 	int			 vararg;
143 	char			*args[MAXWELEM];
144 	struct op		*body;
145 	int			(*nativefn)(int);
146 };
147 
148 TAILQ_HEAD(tests, test);
149 struct test {
150 	TAILQ_ENTRY(test)	 entry;
151 	int			 shouldfail;
152 	char			*name;
153 	struct op		*body;
154 };
155 
156 enum {
157 	EVAL_OK,
158 	EVAL_ERR,
159 	EVAL_SKIP,
160 };
161 
162 int		 global_set(char *, struct op *);
163 
164 struct op	*newop(int);
165 void		 free_op_rec(struct op *);
166 void		 free_op(struct op *);
167 struct op	*op_rest(void);
168 struct op	*op_assign(char *, struct op *);
169 struct op	*op_assert(struct op *);
170 struct op	*op_var(char *);
171 struct op	*op_lit_str(char *);
172 struct op	*op_lit_num(uint64_t);
173 struct op	*op_cmp_eq(struct op *, struct op *);
174 struct op	*op_cmp_leq(struct op *, struct op *);
175 struct op	*op_cast(struct op *, int);
176 struct op	*op_faccess(struct op *, char *);
177 struct op	*op_sfail(struct op *, char *);
178 struct op	*op_vargs(void);
179 
180 void		 ppf_val(FILE *, const struct value *);
181 void		 pp_val(const struct value *);
182 const char	*val_type(struct value *);
183 int		 val_trueish(struct value *);
184 int		 val_isnum(struct value *);
185 int64_t		 val_tonum(struct value *);
186 int		 val_eq(struct value *, struct value *);
187 int		 val_leq(struct value *, struct value *);
188 int		 val_cast(struct value *, int);
189 int		 val_faccess(struct value *, const char *, struct value *);
190 void		 pp_op(struct op *);
191 void		 pp_block(struct op *);
192 int		 eval(struct op *);
193 
194 /* funcall */
195 void		 prepare_funcall(void);
196 void		 push_arg(struct op *);
197 struct op	*op_funcall(struct proc *);
198 
199 /* proc */
200 void		 add_builtin_proc(const char *name, int (*)(int), int, int);
201 void		 prepare_proc(void);
202 /* push_arg works on procs too */
203 int		 proc_setup_body(void);
204 void		 proc_done(char *name);
205 void		 block_push(struct op *);
206 struct proc	*proc_by_name(const char *);
207 
208 /* testing */
209 void		 prepare_test(void);
210 void		 test_done(int, char *);
211 
212 /* np.y */
213 void		 loadfile(const char *);
214 
215 #endif