/* * Copyright (c) 2020 Calvin Rose * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #ifndef JANET_AMALG #include "features.h" #include #include #include "util.h" #include "vector.h" #include "util.h" #endif #ifdef JANET_PEG /* * Runtime */ /* Hold captured patterns and match state */ typedef struct { const uint8_t *text_start; const uint8_t *text_end; const uint32_t *bytecode; const Janet *constants; JanetArray *captures; JanetBuffer *scratch; JanetBuffer *tags; JanetArray *tagged_captures; const Janet *extrav; int32_t *linemap; int32_t extrac; int32_t depth; int32_t linemaplen; int32_t has_backref; enum { PEG_MODE_NORMAL, PEG_MODE_ACCUMULATE } mode; } PegState; /* Allow backtrack with captures. We need * to save state at branches, and then reload * if one branch fails and try a new branch. */ typedef struct { int32_t cap; int32_t tcap; int32_t scratch; } CapState; /* Save the current capture state */ static CapState cap_save(PegState *s) { CapState cs; cs.scratch = s->scratch->count; cs.cap = s->captures->count; cs.tcap = s->tagged_captures->count; return cs; } /* Load a saved capture state in the case of failure */ static void cap_load(PegState *s, CapState cs) { s->scratch->count = cs.scratch; s->captures->count = cs.cap; s->tags->count = cs.tcap; s->tagged_captures->count = cs.tcap; } /* Load a saved capture state in the case of success. Keeps * tagged captures around for backref. */ static void cap_load_keept(PegState *s, CapState cs) { s->scratch->count = cs.scratch; s->captures->count = cs.cap; } /* Add a capture */ static void pushcap(PegState *s, Janet capture, uint32_t tag) { if (s->mode == PEG_MODE_ACCUMULATE) { janet_to_string_b(s->scratch, capture); } if (s->mode == PEG_MODE_NORMAL) { janet_array_push(s->captures, capture); } if (s->has_backref) { janet_array_push(s->tagged_captures, capture); janet_buffer_push_u8(s->tags, tag); } } /* Lazily generate line map to get line and column information for PegState. * line and column are 1-indexed. */ typedef struct { int32_t line; int32_t col; } LineCol; static LineCol get_linecol_from_position(PegState *s, int32_t position) { /* Generate if not made yet */ if (s->linemaplen < 0) { int32_t newline_count = 0; for (const uint8_t *c = s->text_start; c < s->text_end; c++) { if (*c == '\n') newline_count++; } int32_t *mem = janet_smalloc(sizeof(int32_t) * newline_count); size_t index = 0; for (const uint8_t *c = s->text_start; c < s->text_end; c++) { if (*c == '\n') mem[index++] = (int32_t)(c - s->text_start); } s->linemaplen = newline_count; s->linemap = mem; } /* Do binary search for line. Slightly modified from classic binary search: * - if we find that our current character is a line break, just return immediately. * a newline character is consider to be on the same line as the character before * (\n is line terminator, not line separator). * - in the not-found case, we still want to find the greatest-indexed newline that * is before position. we use that to calcuate the line and column. * - in the case that lo = 0 and s->linemap[0] is still greater than position, we * are on the first line and our column is position + 1. */ int32_t hi = s->linemaplen; /* hi is greater than the actual line */ int32_t lo = 0; /* lo is less than or equal to the actual line */ LineCol ret; while (lo + 1 < hi) { int32_t mid = lo + (hi - lo) / 2; if (s->linemap[mid] >= position) { hi = mid; } else { lo = mid; } } /* first line case */ if (s->linemaplen == 0 || (lo == 0 && s->linemap[0] >= position)) { ret.line = 1; ret.col = position + 1; } else { ret.line = lo + 2; ret.col = position - s->linemap[lo]; } return ret; } /* Convert a uint64_t to a int64_t by wrapping to a maximum number of bytes */ static int64_t peg_convert_u64_s64(uint64_t from, int width) { int shift = 8 * (8 - width); return ((int64_t)(from << shift)) >> shift; } /* Prevent stack overflow */ #define down1(s) do { \ if (0 == --((s)->depth)) janet_panic("peg/match recursed too deeply"); \ } while (0) #define up1(s) ((s)->depth++) /* Evaluate a peg rule * Pre-conditions: s is in a valid state * Post-conditions: If there is a match, returns a pointer to the next text. * All captures on the capture stack are valid. If there is no match, * returns NULL. Extra captures from successful child expressions can be * left on the capture stack. */ static const uint8_t *peg_rule( PegState *s, const uint32_t *rule, const uint8_t *text) { tail: switch (*rule & 0x1F) { default: janet_panic("unexpected opcode"); return NULL; case RULE_LITERAL: { uint32_t len = rule[1]; if (text + len > s->text_end) return NULL; return memcmp(text, rule + 2, len) ? NULL : text + len; } case RULE_NCHAR: { uint32_t n = rule[1]; return (text + n > s->text_end) ? NULL : text + n; } case RULE_NOTNCHAR: { uint32_t n = rule[1]; return (text + n > s->text_end) ? text : NULL; } case RULE_RANGE: { uint8_t lo = rule[1] & 0xFF; uint8_t hi = (rule[1] >> 16) & 0xFF; return (text < s->text_end && text[0] >= lo && text[0] <= hi) ? text + 1 : NULL; } case RULE_SET: { uint32_t word = rule[1 + (text[0] >> 5)]; uint32_t mask = (uint32_t)1 << (text[0] & 0x1F); return (text < s->text_end && (word & mask)) ? text + 1 : NULL; } case RULE_LOOK: { text += ((int32_t *)rule)[1]; if (text < s->text_start || text > s->text_end) return NULL; down1(s); const uint8_t *result = peg_rule(s, s->bytecode + rule[2], text); up1(s); text -= ((int32_t *)rule)[1]; return result ? text : NULL; } case RULE_CHOICE: { uint32_t len = rule[1]; const uint32_t *args = rule + 2; if (len == 0) return NULL; down1(s); CapState cs = cap_save(s); for (uint32_t i = 0; i < len - 1; i++) { const uint8_t *result = peg_rule(s, s->bytecode + args[i], text); if (result) { up1(s); return result; } cap_load(s, cs); } up1(s); rule = s->bytecode + args[len - 1]; goto tail; } case RULE_SEQUENCE: { uint32_t len = rule[1]; const uint32_t *args = rule + 2; if (len == 0) return text; down1(s); for (uint32_t i = 0; text && i < len - 1; i++) text = peg_rule(s, s->bytecode + args[i], text); up1(s); if (!text) return NULL; rule = s->bytecode + args[len - 1]; goto tail; } case RULE_IF: case RULE_IFNOT: { const uint32_t *rule_a = s->bytecode + rule[1]; const uint32_t *rule_b = s->bytecode + rule[2]; down1(s); const uint8_t *result = peg_rule(s, rule_a, text); up1(s); if (rule[0] == RULE_IF ? !result : !!result) return NULL; rule = rule_b; goto tail; } case RULE_NOT: { const uint32_t *rule_a = s->bytecode + rule[1]; down1(s); const uint8_t *result = peg_rule(s, rule_a, text); up1(s); return (result) ? NULL : text; } case RULE_THRU: case RULE_TO: { const uint32_t *rule_a = s->bytecode + rule[1]; const uint8_t *next_text; CapState cs = cap_save(s); down1(s); while (text <= s->text_end) { CapState cs2 = cap_save(s); next_text = peg_rule(s, rule_a, text); if (next_text) { if (rule[0] == RULE_TO) cap_load(s, cs2); break; } text++; } up1(s); if (text > s->text_end) { cap_load(s, cs); return NULL; } return rule[0] == RULE_TO ? text : next_text; } case RULE_BETWEEN: { uint32_t lo = rule[1]; uint32_t hi = rule[2]; const uint32_t *rule_a = s->bytecode + rule[3]; uint32_t captured = 0; const uint8_t *next_text; CapState cs = cap_save(s); down1(s); while (captured < hi) { CapState cs2 = cap_save(s); next_text = peg_rule(s, rule_a, text); if (!next_text || next_text == text) { cap_load(s, cs2); break; } captured++; text = next_text; } up1(s); if (captured < lo) { cap_load(s, cs); return NULL; } return text; } /* Capturing rules */ case RULE_GETTAG: { uint32_t search = rule[1]; uint32_t tag = rule[2]; for (int32_t i = s->tags->count - 1; i >= 0; i--) { if (s->tags->data[i] == search) { pushcap(s, s->tagged_captures->data[i], tag); return text; } } return NULL; } case RULE_POSITION: { pushcap(s, janet_wrap_number((double)(text - s->text_start)), rule[1]); return text; } case RULE_LINE: { LineCol lc = get_linecol_from_position(s, (int32_t)(text - s->text_start)); pushcap(s, janet_wrap_number((double)(lc.line)), rule[1]); return text; } case RULE_COLUMN: { LineCol lc = get_linecol_from_position(s, (int32_t)(text - s->text_start)); pushcap(s, janet_wrap_number((double)(lc.col)), rule[1]); return text; } case RULE_ARGUMENT: { int32_t index = ((int32_t *)rule)[1]; Janet capture = (index >= s->extrac) ? janet_wrap_nil() : s->extrav[index]; pushcap(s, capture, rule[2]); return text; } case RULE_CONSTANT: { pushcap(s, s->constants[rule[1]], rule[2]); return text; } case RULE_CAPTURE: { down1(s); const uint8_t *result = peg_rule(s, s->bytecode + rule[1], text); up1(s); if (!result) return NULL; /* Specialized pushcap - avoid intermediate string creation */ if (!s->has_backref && s->mode == PEG_MODE_ACCUMULATE) { janet_buffer_push_bytes(s->scratch, text, (int32_t)(result - text)); } else { uint32_t tag = rule[2]; pushcap(s, janet_stringv(text, (int32_t)(result - text)), tag); } return result; } case RULE_ACCUMULATE: { uint32_t tag = rule[2]; int oldmode = s->mode; if (!tag && oldmode == PEG_MODE_ACCUMULATE) { rule = s->bytecode + rule[1]; goto tail; } CapState cs = cap_save(s); s->mode = PEG_MODE_ACCUMULATE; down1(s); const uint8_t *result = peg_rule(s, s->bytecode + rule[1], text); up1(s); s->mode = oldmode; if (!result) return NULL; Janet cap = janet_stringv(s->scratch->data + cs.scratch, s->scratch->count - cs.scratch); cap_load_keept(s, cs); pushcap(s, cap, tag); return result; } case RULE_DROP: { CapState cs = cap_save(s); down1(s); const uint8_t *result = peg_rule(s, s->bytecode + rule[1], text); up1(s); if (!result) return NULL; cap_load(s, cs); return result; } case RULE_GROUP: { uint32_t tag = rule[2]; int oldmode = s->mode; CapState cs = cap_save(s); s->mode = PEG_MODE_NORMAL; down1(s); const uint8_t *result = peg_rule(s, s->bytecode + rule[1], text); up1(s); s->mode = oldmode; if (!result) return NULL; int32_t num_sub_captures = s->captures->count - cs.cap; JanetArray *sub_captures = janet_array(num_sub_captures); safe_memcpy(sub_captures->data, s->captures->data + cs.cap, sizeof(Janet) * num_sub_captures); sub_captures->count = num_sub_captures; cap_load_keept(s, cs); pushcap(s, janet_wrap_array(sub_captures), tag); return result; } case RULE_REPLACE: case RULE_MATCHTIME: { uint32_t tag = rule[3]; int oldmode = s->mode; CapState cs = cap_save(s); s->mode = PEG_MODE_NORMAL; down1(s); const uint8_t *result = peg_rule(s, s->bytecode + rule[1], text); up1(s); s->mode = oldmode; if (!result) return NULL; Janet cap = janet_wrap_nil(); Janet constant = s->constants[rule[2]]; switch (janet_type(constant)) { default: cap = constant; break; case JANET_STRUCT: if (s->captures->count) { cap = janet_struct_get(janet_unwrap_struct(constant), s->captures->data[s->captures->count - 1]); } break; case JANET_TABLE: if (s->captures->count) { cap = janet_table_get(janet_unwrap_table(constant), s->captures->data[s->captures->count - 1]); } break; case JANET_CFUNCTION: cap = janet_unwrap_cfunction(constant)(s->captures->count - cs.cap, s->captures->data + cs.cap); break; case JANET_FUNCTION: cap = janet_call(janet_unwrap_function(constant), s->captures->count - cs.cap, s->captures->data + cs.cap); break; } cap_load_keept(s, cs); if (rule[0] == RULE_MATCHTIME && !janet_truthy(cap)) return NULL; pushcap(s, cap, tag); return result; } case RULE_ERROR: { int oldmode = s->mode; s->mode = PEG_MODE_NORMAL; int32_t old_cap = s->captures->count; down1(s); const uint8_t *result = peg_rule(s, s->bytecode + rule[1], text); up1(s); s->mode = oldmode; if (!result) return NULL; if (s->captures->count > old_cap) { /* Throw last capture */ janet_panicv(s->captures->data[s->captures->count - 1]); } else { /* Throw generic error */ int32_t start = (int32_t)(text - s->text_start); LineCol lc = get_linecol_from_position(s, start); janet_panicf("match error at line %d, column %d", lc.line, lc.col); } return NULL; } case RULE_BACKMATCH: { uint32_t search = rule[1]; for (int32_t i = s->tags->count - 1; i >= 0; i--) { if (s->tags->data[i] == search) { Janet capture = s->tagged_captures->data[i]; if (!janet_checktype(capture, JANET_STRING)) return NULL; const uint8_t *bytes = janet_unwrap_string(capture); int32_t len = janet_string_length(bytes); if (text + len > s->text_end) return NULL; return memcmp(text, bytes, len) ? NULL : text + len; } } return NULL; } case RULE_LENPREFIX: { int oldmode = s->mode; s->mode = PEG_MODE_NORMAL; const uint8_t *next_text; CapState cs = cap_save(s); down1(s); next_text = peg_rule(s, s->bytecode + rule[1], text); up1(s); if (NULL == next_text) return NULL; s->mode = oldmode; int32_t num_sub_captures = s->captures->count - cs.cap; Janet lencap; if (num_sub_captures <= 0 || (lencap = s->captures->data[cs.cap], !janet_checkint(lencap))) { cap_load(s, cs); return NULL; } int32_t nrep = janet_unwrap_integer(lencap); /* drop captures from len pattern */ cap_load(s, cs); for (int32_t i = 0; i < nrep; i++) { down1(s); next_text = peg_rule(s, s->bytecode + rule[2], next_text); up1(s); if (NULL == next_text) { cap_load(s, cs); return NULL; } } return next_text; } case RULE_READINT: { uint32_t tag = rule[2]; uint32_t signedness = rule[1] & 0x10; uint32_t endianess = rule[1] & 0x20; int width = (int)(rule[1] & 0xF); if (text + width > s->text_end) return NULL; uint64_t accum = 0; if (endianess) { /* BE */ for (int i = 0; i < width; i++) accum = (accum << 8) | text[i]; } else { /* LE */ for (int i = width - 1; i >= 0; i--) accum = (accum << 8) | text[i]; } Janet capture_value; /* We can only parse integeres of greater than 6 bytes reliable if int-types are enabled. * Otherwise, we may lose precision, so 6 is the maximum size when int-types are disabled. */ #ifdef JANET_INT_TYPES if (width > 6) { if (signedness) { capture_value = janet_wrap_s64(peg_convert_u64_s64(accum, width)); } else { capture_value = janet_wrap_u64(accum); } } else #endif { double double_value; if (signedness) { double_value = (double)(peg_convert_u64_s64(accum, width)); } else { double_value = (double)accum; } capture_value = janet_wrap_number(double_value); } pushcap(s, capture_value, tag); return text + width; } } } /* * Compilation */ typedef struct { JanetTable *grammar; JanetTable *default_grammar; JanetTable *tags; Janet *constants; uint32_t *bytecode; Janet form; int depth; uint32_t nexttag; int has_backref; } Builder; /* Forward declaration to allow recursion */ static uint32_t peg_compile1(Builder *b, Janet peg); /* * Errors */ static void builder_cleanup(Builder *b) { janet_v_free(b->constants); janet_v_free(b->bytecode); } JANET_NO_RETURN static void peg_panic(Builder *b, const char *msg) { builder_cleanup(b); janet_panicf("grammar error in %p, %s", b->form, msg); } #define peg_panicf(b,...) peg_panic((b), (const char *) janet_formatc(__VA_ARGS__)) static void peg_fixarity(Builder *b, int32_t argc, int32_t arity) { if (argc != arity) { peg_panicf(b, "expected %d argument%s, got %d", arity, arity == 1 ? "" : "s", argc); } } static void peg_arity(Builder *b, int32_t arity, int32_t min, int32_t max) { if (min >= 0 && arity < min) peg_panicf(b, "arity mismatch, expected at least %d, got %d", min, arity); if (max >= 0 && arity > max) peg_panicf(b, "arity mismatch, expected at most %d, got %d", max, arity); } static const uint8_t *peg_getset(Builder *b, Janet x) { if (!janet_checktype(x, JANET_STRING)) peg_panic(b, "expected string for character set"); const uint8_t *str = janet_unwrap_string(x); return str; } static const uint8_t *peg_getrange(Builder *b, Janet x) { if (!janet_checktype(x, JANET_STRING)) peg_panic(b, "expected string for character range"); const uint8_t *str = janet_unwrap_string(x); if (janet_string_length(str) != 2) peg_panicf(b, "expected string to have length 2, got %v", x); if (str[1] < str[0]) peg_panicf(b, "range %v is empty", x); return str; } static int32_t peg_getinteger(Builder *b, Janet x) { if (!janet_checkint(x)) peg_panicf(b, "expected integer, got %v", x); return janet_unwrap_integer(x); } static int32_t peg_getnat(Builder *b, Janet x) { int32_t i = peg_getinteger(b, x); if (i < 0) peg_panicf(b, "expected non-negative integer, got %v", x); return i; } /* * Emission */ static uint32_t emit_constant(Builder *b, Janet c) { uint32_t cindex = (uint32_t) janet_v_count(b->constants); janet_v_push(b->constants, c); return cindex; } static uint32_t emit_tag(Builder *b, Janet t) { if (!janet_checktype(t, JANET_KEYWORD)) peg_panicf(b, "expected keyword for capture tag, got %v", t); Janet check = janet_table_get(b->tags, t); if (janet_checktype(check, JANET_NIL)) { uint32_t tag = b->nexttag++; if (tag > 255) { peg_panic(b, "too many tags - up to 255 tags are supported per peg"); } Janet val = janet_wrap_number(tag); janet_table_put(b->tags, t, val); return tag; } else { return (uint32_t) janet_unwrap_number(check); } } /* Reserve space in bytecode for a rule. When a special emits a rule, * it must place that rule immediately on the bytecode stack. This lets * the compiler know where the rule is going to be before it is complete, * allowing recursive rules. */ typedef struct { Builder *builder; uint32_t index; int32_t size; } Reserve; static Reserve reserve(Builder *b, int32_t size) { Reserve r; r.index = janet_v_count(b->bytecode); r.builder = b; r.size = size; for (int32_t i = 0; i < size; i++) janet_v_push(b->bytecode, 0); return r; } /* Emit a rule in the builder. Returns the index of the new rule */ static void emit_rule(Reserve r, int32_t op, int32_t n, const uint32_t *body) { janet_assert(r.size == n + 1, "bad reserve"); r.builder->bytecode[r.index] = op; memcpy(r.builder->bytecode + r.index + 1, body, n * sizeof(uint32_t)); } /* For RULE_LITERAL */ static void emit_bytes(Builder *b, uint32_t op, int32_t len, const uint8_t *bytes) { uint32_t next_rule = janet_v_count(b->bytecode); janet_v_push(b->bytecode, op); janet_v_push(b->bytecode, len); int32_t words = ((len + 3) >> 2); for (int32_t i = 0; i < words; i++) janet_v_push(b->bytecode, 0); memcpy(b->bytecode + next_rule + 2, bytes, len); } /* For fixed arity rules of arities 1, 2, and 3 */ static void emit_1(Reserve r, uint32_t op, uint32_t arg) { emit_rule(r, op, 1, &arg); } static void emit_2(Reserve r, uint32_t op, uint32_t arg1, uint32_t arg2) { uint32_t arr[2] = {arg1, arg2}; emit_rule(r, op, 2, arr); } static void emit_3(Reserve r, uint32_t op, uint32_t arg1, uint32_t arg2, uint32_t arg3) { uint32_t arr[3] = {arg1, arg2, arg3}; emit_rule(r, op, 3, arr); } /* * Specials */ static void bitmap_set(uint32_t *bitmap, uint8_t c) { bitmap[c >> 5] |= ((uint32_t)1) << (c & 0x1F); } static void spec_range(Builder *b, int32_t argc, const Janet *argv) { peg_arity(b, argc, 1, -1); if (argc == 1) { Reserve r = reserve(b, 2); const uint8_t *str = peg_getrange(b, argv[0]); uint32_t arg = str[0] | (str[1] << 16); emit_1(r, RULE_RANGE, arg); } else { /* Compile as a set */ Reserve r = reserve(b, 9); uint32_t bitmap[8] = {0}; for (int32_t i = 0; i < argc; i++) { const uint8_t *str = peg_getrange(b, argv[i]); for (uint32_t c = str[0]; c <= str[1]; c++) bitmap_set(bitmap, c); } emit_rule(r, RULE_SET, 8, bitmap); } } static void spec_set(Builder *b, int32_t argc, const Janet *argv) { peg_fixarity(b, argc, 1); Reserve r = reserve(b, 9); const uint8_t *str = peg_getset(b, argv[0]); uint32_t bitmap[8] = {0}; for (int32_t i = 0; i < janet_string_length(str); i++) bitmap_set(bitmap, str[i]); emit_rule(r, RULE_SET, 8, bitmap); } static void spec_look(Builder *b, int32_t argc, const Janet *argv) { peg_arity(b, argc, 1, 2); Reserve r = reserve(b, 3); int32_t rulearg = argc == 2 ? 1 : 0; int32_t offset = argc == 2 ? peg_getinteger(b, argv[0]) : 0; uint32_t subrule = peg_compile1(b, argv[rulearg]); emit_2(r, RULE_LOOK, (uint32_t) offset, subrule); } /* Rule of the form [len, rules...] */ static void spec_variadic(Builder *b, int32_t argc, const Janet *argv, uint32_t op) { uint32_t rule = janet_v_count(b->bytecode); janet_v_push(b->bytecode, op); janet_v_push(b->bytecode, argc); for (int32_t i = 0; i < argc; i++) janet_v_push(b->bytecode, 0); for (int32_t i = 0; i < argc; i++) { uint32_t rulei = peg_compile1(b, argv[i]); b->bytecode[rule + 2 + i] = rulei; } } static void spec_choice(Builder *b, int32_t argc, const Janet *argv) { spec_variadic(b, argc, argv, RULE_CHOICE); } static void spec_sequence(Builder *b, int32_t argc, const Janet *argv) { spec_variadic(b, argc, argv, RULE_SEQUENCE); } /* For (if a b) and (if-not a b) */ static void spec_branch(Builder *b, int32_t argc, const Janet *argv, uint32_t rule) { peg_fixarity(b, argc, 2); Reserve r = reserve(b, 3); uint32_t rule_a = peg_compile1(b, argv[0]); uint32_t rule_b = peg_compile1(b, argv[1]); emit_2(r, rule, rule_a, rule_b); } static void spec_if(Builder *b, int32_t argc, const Janet *argv) { spec_branch(b, argc, argv, RULE_IF); } static void spec_ifnot(Builder *b, int32_t argc, const Janet *argv) { spec_branch(b, argc, argv, RULE_IFNOT); } static void spec_lenprefix(Builder *b, int32_t argc, const Janet *argv) { spec_branch(b, argc, argv, RULE_LENPREFIX); } static void spec_between(Builder *b, int32_t argc, const Janet *argv) { peg_fixarity(b, argc, 3); Reserve r = reserve(b, 4); int32_t lo = peg_getnat(b, argv[0]); int32_t hi = peg_getnat(b, argv[1]); uint32_t subrule = peg_compile1(b, argv[2]); emit_3(r, RULE_BETWEEN, lo, hi, subrule); } static void spec_repeater(Builder *b, int32_t argc, const Janet *argv, int32_t min) { peg_fixarity(b, argc, 1); Reserve r = reserve(b, 4); uint32_t subrule = peg_compile1(b, argv[0]); emit_3(r, RULE_BETWEEN, min, UINT32_MAX, subrule); } static void spec_some(Builder *b, int32_t argc, const Janet *argv) { spec_repeater(b, argc, argv, 1); } static void spec_any(Builder *b, int32_t argc, const Janet *argv) { spec_repeater(b, argc, argv, 0); } static void spec_atleast(Builder *b, int32_t argc, const Janet *argv) { peg_fixarity(b, argc, 2); Reserve r = reserve(b, 4); int32_t n = peg_getnat(b, argv[0]); uint32_t subrule = peg_compile1(b, argv[1]); emit_3(r, RULE_BETWEEN, n, UINT32_MAX, subrule); } static void spec_atmost(Builder *b, int32_t argc, const Janet *argv) { peg_fixarity(b, argc, 2); Reserve r = reserve(b, 4); int32_t n = peg_getnat(b, argv[0]); uint32_t subrule = peg_compile1(b, argv[1]); emit_3(r, RULE_BETWEEN, 0, n, subrule); } static void spec_opt(Builder *b, int32_t argc, const Janet *argv) { peg_fixarity(b, argc, 1); Reserve r = reserve(b, 4); uint32_t subrule = peg_compile1(b, argv[0]); emit_3(r, RULE_BETWEEN, 0, 1, subrule); } static void spec_repeat(Builder *b, int32_t argc, const Janet *argv) { peg_fixarity(b, argc, 2); Reserve r = reserve(b, 4); int32_t n = peg_getnat(b, argv[0]); uint32_t subrule = peg_compile1(b, argv[1]); emit_3(r, RULE_BETWEEN, n, n, subrule); } /* Rule of the form [rule] */ static void spec_onerule(Builder *b, int32_t argc, const Janet *argv, uint32_t op) { peg_fixarity(b, argc, 1); Reserve r = reserve(b, 2); uint32_t rule = peg_compile1(b, argv[0]); emit_1(r, op, rule); } static void spec_not(Builder *b, int32_t argc, const Janet *argv) { spec_onerule(b, argc, argv, RULE_NOT); } static void spec_error(Builder *b, int32_t argc, const Janet *argv) { if (argc == 0) { Reserve r = reserve(b, 2); uint32_t rule = peg_compile1(b, janet_wrap_number(0)); emit_1(r, RULE_ERROR, rule); } else { spec_onerule(b, argc, argv, RULE_ERROR); } } static void spec_drop(Builder *b, int32_t argc, const Janet *argv) { spec_onerule(b, argc, argv, RULE_DROP); } static void spec_to(Builder *b, int32_t argc, const Janet *argv) { spec_onerule(b, argc, argv, RULE_TO); } static void spec_thru(Builder *b, int32_t argc, const Janet *argv) { spec_onerule(b, argc, argv, RULE_THRU); } /* Rule of the form [rule, tag] */ static void spec_cap1(Builder *b, int32_t argc, const Janet *argv, uint32_t op) { peg_arity(b, argc, 1, 2); Reserve r = reserve(b, 3); uint32_t tag = (argc == 2) ? emit_tag(b, argv[1]) : 0; uint32_t rule = peg_compile1(b, argv[0]); emit_2(r, op, rule, tag); } static void spec_capture(Builder *b, int32_t argc, const Janet *argv) { spec_cap1(b, argc, argv, RULE_CAPTURE); } static void spec_accumulate(Builder *b, int32_t argc, const Janet *argv) { spec_cap1(b, argc, argv, RULE_ACCUMULATE); } static void spec_group(Builder *b, int32_t argc, const Janet *argv) { spec_cap1(b, argc, argv, RULE_GROUP); } static void spec_reference(Builder *b, int32_t argc, const Janet *argv) { peg_arity(b, argc, 1, 2); Reserve r = reserve(b, 3); uint32_t search = emit_tag(b, argv[0]); uint32_t tag = (argc == 2) ? emit_tag(b, argv[1]) : 0; b->has_backref = 1; emit_2(r, RULE_GETTAG, search, tag); } static void spec_tag1(Builder *b, int32_t argc, const Janet *argv, uint32_t op) { peg_arity(b, argc, 0, 1); Reserve r = reserve(b, 2); uint32_t tag = (argc) ? emit_tag(b, argv[0]) : 0; (void) argv; emit_1(r, op, tag); } static void spec_position(Builder *b, int32_t argc, const Janet *argv) { spec_tag1(b, argc, argv, RULE_POSITION); } static void spec_line(Builder *b, int32_t argc, const Janet *argv) { spec_tag1(b, argc, argv, RULE_LINE); } static void spec_column(Builder *b, int32_t argc, const Janet *argv) { spec_tag1(b, argc, argv, RULE_COLUMN); } static void spec_backmatch(Builder *b, int32_t argc, const Janet *argv) { b->has_backref = 1; spec_tag1(b, argc, argv, RULE_BACKMATCH); } static void spec_argument(Builder *b, int32_t argc, const Janet *argv) { peg_arity(b, argc, 1, 2); Reserve r = reserve(b, 3); uint32_t tag = (argc == 2) ? emit_tag(b, argv[1]) : 0; int32_t index = peg_getnat(b, argv[0]); emit_2(r, RULE_ARGUMENT, index, tag); } static void spec_constant(Builder *b, int32_t argc, const Janet *argv) { janet_arity(argc, 1, 2); Reserve r = reserve(b, 3); uint32_t tag = (argc == 2) ? emit_tag(b, argv[1]) : 0; emit_2(r, RULE_CONSTANT, emit_constant(b, argv[0]), tag); } static void spec_replace(Builder *b, int32_t argc, const Janet *argv) { peg_arity(b, argc, 2, 3); Reserve r = reserve(b, 4); uint32_t subrule = peg_compile1(b, argv[0]); uint32_t constant = emit_constant(b, argv[1]); uint32_t tag = (argc == 3) ? emit_tag(b, argv[2]) : 0; emit_3(r, RULE_REPLACE, subrule, constant, tag); } static void spec_matchtime(Builder *b, int32_t argc, const Janet *argv) { peg_arity(b, argc, 2, 3); Reserve r = reserve(b, 4); uint32_t subrule = peg_compile1(b, argv[0]); Janet fun = argv[1]; if (!janet_checktype(fun, JANET_FUNCTION) && !janet_checktype(fun, JANET_CFUNCTION)) { peg_panicf(b, "expected function|cfunction, got %v", fun); } uint32_t tag = (argc == 3) ? emit_tag(b, argv[2]) : 0; uint32_t cindex = emit_constant(b, fun); emit_3(r, RULE_MATCHTIME, subrule, cindex, tag); } #ifdef JANET_INT_TYPES #define JANET_MAX_READINT_WIDTH 8 #else #define JANET_MAX_READINT_WIDTH 6 #endif static void spec_readint(Builder *b, int32_t argc, const Janet *argv, uint32_t mask) { peg_arity(b, argc, 1, 2); Reserve r = reserve(b, 3); uint32_t tag = (argc == 2) ? emit_tag(b, argv[1]) : 0; int32_t width = peg_getnat(b, argv[0]); if ((width < 0) || (width > JANET_MAX_READINT_WIDTH)) { peg_panicf(b, "width must be between 0 and %d, got %d", JANET_MAX_READINT_WIDTH, width); } emit_2(r, RULE_READINT, mask | ((uint32_t) width), tag); } static void spec_uint_le(Builder *b, int32_t argc, const Janet *argv) { spec_readint(b, argc, argv, 0x0u); } static void spec_int_le(Builder *b, int32_t argc, const Janet *argv) { spec_readint(b, argc, argv, 0x10u); } static void spec_uint_be(Builder *b, int32_t argc, const Janet *argv) { spec_readint(b, argc, argv, 0x20u); } static void spec_int_be(Builder *b, int32_t argc, const Janet *argv) { spec_readint(b, argc, argv, 0x30u); } /* Special compiler form */ typedef void (*Special)(Builder *b, int32_t argc, const Janet *argv); typedef struct { const char *name; Special special; } SpecialPair; /* Keep in lexical order (vim :sort works well) */ static const SpecialPair peg_specials[] = { {"!", spec_not}, {"$", spec_position}, {"%", spec_accumulate}, {"*", spec_sequence}, {"+", spec_choice}, {"->", spec_reference}, {"/", spec_replace}, {"<-", spec_capture}, {">", spec_look}, {"?", spec_opt}, {"accumulate", spec_accumulate}, {"any", spec_any}, {"argument", spec_argument}, {"at-least", spec_atleast}, {"at-most", spec_atmost}, {"backmatch", spec_backmatch}, {"backref", spec_reference}, {"between", spec_between}, {"capture", spec_capture}, {"choice", spec_choice}, {"cmt", spec_matchtime}, {"column", spec_column}, {"constant", spec_constant}, {"drop", spec_drop}, {"error", spec_error}, {"group", spec_group}, {"if", spec_if}, {"if-not", spec_ifnot}, {"int", spec_int_le}, {"int-be", spec_int_be}, {"lenprefix", spec_lenprefix}, {"line", spec_line}, {"look", spec_look}, {"not", spec_not}, {"opt", spec_opt}, {"position", spec_position}, {"quote", spec_capture}, {"range", spec_range}, {"repeat", spec_repeat}, {"replace", spec_replace}, {"sequence", spec_sequence}, {"set", spec_set}, {"some", spec_some}, {"thru", spec_thru}, {"to", spec_to}, {"uint", spec_uint_le}, {"uint-be", spec_uint_be}, }; /* Compile a janet value into a rule and return the rule index. */ static uint32_t peg_compile1(Builder *b, Janet peg) { /* Keep track of the form being compiled for error purposes */ Janet old_form = b->form; JanetTable *old_grammar = b->grammar; b->form = peg; /* Resolve keyword references */ int i = JANET_RECURSION_GUARD; JanetTable *grammar = old_grammar; for (; i > 0 && janet_checktype(peg, JANET_KEYWORD); --i) { Janet nextPeg = janet_table_get_ex(grammar, peg, &grammar); if (!grammar || janet_checktype(nextPeg, JANET_NIL)) { nextPeg = janet_table_get(b->default_grammar, peg); if (janet_checktype(nextPeg, JANET_NIL)) { peg_panic(b, "unknown rule"); } } peg = nextPeg; b->form = peg; b->grammar = grammar; } if (i == 0) peg_panic(b, "reference chain too deep"); /* Check cache - for tuples we check only the local cache, as * in a different grammar, the same tuple can compile to a different * rule - for example, (+ :a :b) depends on whatever :a and :b are bound to. */ Janet check = janet_checktype(peg, JANET_TUPLE) ? janet_table_rawget(grammar, peg) : janet_table_get(grammar, peg); if (!janet_checktype(check, JANET_NIL)) { b->form = old_form; b->grammar = old_grammar; return (uint32_t) janet_unwrap_number(check); } /* Check depth */ if (b->depth-- == 0) peg_panic(b, "peg grammar recursed too deeply"); /* The final rule to return */ uint32_t rule = janet_v_count(b->bytecode); /* Add to cache. Do not cache structs, as we don't yet know * what rule they will return! We can just as effectively cache * the structs main rule. */ if (!janet_checktype(peg, JANET_STRUCT)) { JanetTable *which_grammar = grammar; /* If we are a primitive pattern, add to the global cache (root grammar table) */ if (!janet_checktype(peg, JANET_TUPLE)) { while (which_grammar->proto) which_grammar = which_grammar->proto; } janet_table_put(which_grammar, peg, janet_wrap_number(rule)); } switch (janet_type(peg)) { default: peg_panic(b, "unexpected peg source"); return 0; case JANET_NUMBER: { int32_t n = peg_getinteger(b, peg); Reserve r = reserve(b, 2); if (n < 0) { emit_1(r, RULE_NOTNCHAR, -n); } else { emit_1(r, RULE_NCHAR, n); } break; } case JANET_STRING: { const uint8_t *str = janet_unwrap_string(peg); int32_t len = janet_string_length(str); emit_bytes(b, RULE_LITERAL, len, str); break; } case JANET_STRUCT: { /* Build grammar table */ const JanetKV *st = janet_unwrap_struct(peg); JanetTable *new_grammar = janet_table(2 * janet_struct_capacity(st)); for (int32_t i = 0; i < janet_struct_capacity(st); i++) { if (janet_checktype(st[i].key, JANET_KEYWORD)) { janet_table_put(new_grammar, st[i].key, st[i].value); } } new_grammar->proto = grammar; b->grammar = grammar = new_grammar; /* Run the main rule */ Janet main_rule = janet_table_rawget(grammar, janet_ckeywordv("main")); if (janet_checktype(main_rule, JANET_NIL)) peg_panic(b, "grammar requires :main rule"); rule = peg_compile1(b, main_rule); break; } case JANET_TUPLE: { const Janet *tup = janet_unwrap_tuple(peg); int32_t len = janet_tuple_length(tup); if (len == 0) peg_panic(b, "tuple in grammar must have non-zero length"); if (janet_checkint(tup[0])) { int32_t n = janet_unwrap_integer(tup[0]); if (n < 0) { peg_panicf(b, "expected non-negative integer, got %d", n); } spec_repeat(b, len, tup); break; } if (!janet_checktype(tup[0], JANET_SYMBOL)) peg_panicf(b, "expected grammar command, found %v", tup[0]); const uint8_t *sym = janet_unwrap_symbol(tup[0]); const SpecialPair *sp = janet_strbinsearch( &peg_specials, sizeof(peg_specials) / sizeof(SpecialPair), sizeof(SpecialPair), sym); if (sp) { sp->special(b, len - 1, tup + 1); } else { peg_panicf(b, "unknown special %S", sym); } break; } } /* Increase depth again */ b->depth++; b->form = old_form; b->grammar = old_grammar; return rule; } /* * Post-Compilation */ static int peg_mark(void *p, size_t size) { (void) size; JanetPeg *peg = (JanetPeg *)p; if (NULL != peg->constants) for (uint32_t i = 0; i < peg->num_constants; i++) janet_mark(peg->constants[i]); return 0; } static void peg_marshal(void *p, JanetMarshalContext *ctx) { JanetPeg *peg = (JanetPeg *)p; janet_marshal_size(ctx, peg->bytecode_len); janet_marshal_int(ctx, (int32_t)peg->num_constants); janet_marshal_abstract(ctx, p); for (size_t i = 0; i < peg->bytecode_len; i++) janet_marshal_int(ctx, (int32_t) peg->bytecode[i]); for (uint32_t j = 0; j < peg->num_constants; j++) janet_marshal_janet(ctx, peg->constants[j]); } /* Used to ensure that if we place several arrays in one memory chunk, each * array will be correctly aligned */ static size_t size_padded(size_t offset, size_t size) { size_t x = size + offset - 1; return x - (x % size); } static void *peg_unmarshal(JanetMarshalContext *ctx) { size_t bytecode_len = janet_unmarshal_size(ctx); uint32_t num_constants = (uint32_t) janet_unmarshal_int(ctx); /* Calculate offsets. Should match those in make_peg */ size_t bytecode_start = size_padded(sizeof(JanetPeg), sizeof(uint32_t)); size_t bytecode_size = bytecode_len * sizeof(uint32_t); size_t constants_start = size_padded(bytecode_start + bytecode_size, sizeof(Janet)); size_t total_size = constants_start + sizeof(Janet) * (size_t) num_constants; /* DOS prevention? I.E. we could read bytecode and constants before * hand so we don't allocated a ton of memory on bad, short input */ /* Allocate PEG */ char *mem = janet_unmarshal_abstract(ctx, total_size); JanetPeg *peg = (JanetPeg *)mem; uint32_t *bytecode = (uint32_t *)(mem + bytecode_start); Janet *constants = (Janet *)(mem + constants_start); peg->bytecode = NULL; peg->constants = NULL; peg->bytecode_len = bytecode_len; peg->num_constants = num_constants; for (size_t i = 0; i < peg->bytecode_len; i++) bytecode[i] = (uint32_t) janet_unmarshal_int(ctx); for (uint32_t j = 0; j < peg->num_constants; j++) constants[j] = janet_unmarshal_janet(ctx); /* After here, no panics except for the bad: label. */ /* Keep track at each index if an instruction was * reference (0x01) or is in a main bytecode position * (0x02). This lets us do a linear scan and not * need to a depth first traversal. It is stricter * than a dfs by not allowing certain kinds of unused * bytecode. */ uint32_t blen = (int32_t) peg->bytecode_len; uint32_t clen = peg->num_constants; uint8_t *op_flags = calloc(1, blen); if (NULL == op_flags) { JANET_OUT_OF_MEMORY; } /* verify peg bytecode */ int32_t has_backref = 0; uint32_t i = 0; while (i < blen) { uint32_t instr = bytecode[i]; uint32_t *rule = bytecode + i; op_flags[i] |= 0x02; switch (instr & 0x1F) { case RULE_LITERAL: i += 2 + ((rule[1] + 3) >> 2); break; case RULE_NCHAR: case RULE_NOTNCHAR: case RULE_RANGE: case RULE_POSITION: case RULE_LINE: case RULE_COLUMN: /* [1 word] */ i += 2; break; case RULE_BACKMATCH: /* [1 word] */ i += 2; has_backref = 1; break; case RULE_SET: /* [8 words] */ i += 9; break; case RULE_LOOK: /* [offset, rule] */ if (rule[2] >= blen) goto bad; op_flags[rule[2]] |= 0x1; i += 3; break; case RULE_CHOICE: case RULE_SEQUENCE: /* [len, rules...] */ { uint32_t len = rule[1]; for (uint32_t j = 0; j < len; j++) { if (rule[2 + j] >= blen) goto bad; op_flags[rule[2 + j]] |= 0x1; } i += 2 + len; } break; case RULE_IF: case RULE_IFNOT: case RULE_LENPREFIX: /* [rule_a, rule_b (b if not a)] */ if (rule[1] >= blen) goto bad; if (rule[2] >= blen) goto bad; op_flags[rule[1]] |= 0x01; op_flags[rule[2]] |= 0x01; i += 3; break; case RULE_BETWEEN: /* [lo, hi, rule] */ if (rule[3] >= blen) goto bad; op_flags[rule[3]] |= 0x01; i += 4; break; case RULE_ARGUMENT: /* [searchtag, tag] */ i += 3; break; case RULE_GETTAG: /* [searchtag, tag] */ i += 3; has_backref = 1; break; case RULE_CONSTANT: /* [constant, tag] */ if (rule[1] >= clen) goto bad; i += 3; break; case RULE_ACCUMULATE: case RULE_GROUP: case RULE_CAPTURE: /* [rule, tag] */ if (rule[1] >= blen) goto bad; op_flags[rule[1]] |= 0x01; i += 3; break; case RULE_REPLACE: case RULE_MATCHTIME: /* [rule, constant, tag] */ if (rule[1] >= blen) goto bad; if (rule[2] >= clen) goto bad; op_flags[rule[1]] |= 0x01; i += 4; break; case RULE_ERROR: case RULE_DROP: case RULE_NOT: case RULE_TO: case RULE_THRU: /* [rule] */ if (rule[1] >= blen) goto bad; op_flags[rule[1]] |= 0x01; i += 2; break; case RULE_READINT: /* [ width | (endianess << 5) | (signedness << 6), tag ] */ if (rule[1] > JANET_MAX_READINT_WIDTH) goto bad; i += 3; break; default: goto bad; } } /* last instruction cannot overflow */ if (i != blen) goto bad; /* Make sure all referenced instructions are actually * in instruction positions. */ for (i = 0; i < blen; i++) if (op_flags[i] == 0x01) goto bad; /* Good return */ peg->bytecode = bytecode; peg->constants = constants; peg->has_backref = has_backref; free(op_flags); return peg; bad: free(op_flags); janet_panic("invalid peg bytecode"); } static int cfun_peg_getter(JanetAbstract a, Janet key, Janet *out); static Janet peg_next(void *p, Janet key); const JanetAbstractType janet_peg_type = { "core/peg", NULL, peg_mark, cfun_peg_getter, NULL, /* put */ peg_marshal, peg_unmarshal, NULL, /* tostring */ NULL, /* compare */ NULL, /* hash */ peg_next, JANET_ATEND_NEXT }; /* Convert Builder to JanetPeg (Janet Abstract Value) */ static JanetPeg *make_peg(Builder *b) { size_t bytecode_start = size_padded(sizeof(JanetPeg), sizeof(uint32_t)); size_t bytecode_size = janet_v_count(b->bytecode) * sizeof(uint32_t); size_t constants_start = size_padded(bytecode_start + bytecode_size, sizeof(Janet)); size_t constants_size = janet_v_count(b->constants) * sizeof(Janet); size_t total_size = constants_start + constants_size; char *mem = janet_abstract(&janet_peg_type, total_size); JanetPeg *peg = (JanetPeg *)mem; peg->bytecode = (uint32_t *)(mem + bytecode_start); peg->constants = (Janet *)(mem + constants_start); peg->num_constants = janet_v_count(b->constants); safe_memcpy(peg->bytecode, b->bytecode, bytecode_size); safe_memcpy(peg->constants, b->constants, constants_size); peg->bytecode_len = janet_v_count(b->bytecode); peg->has_backref = b->has_backref; return peg; } /* Compiler entry point */ static JanetPeg *compile_peg(Janet x) { Builder builder; builder.grammar = janet_table(0); builder.default_grammar = NULL; { Janet default_grammarv = janet_dyn("peg-grammar"); if (janet_checktype(default_grammarv, JANET_TABLE)) { builder.default_grammar = janet_unwrap_table(default_grammarv); } } builder.tags = janet_table(0); builder.constants = NULL; builder.bytecode = NULL; builder.nexttag = 1; builder.form = x; builder.depth = JANET_RECURSION_GUARD; builder.has_backref = 0; peg_compile1(&builder, x); JanetPeg *peg = make_peg(&builder); builder_cleanup(&builder); return peg; } /* * C Functions */ static Janet cfun_peg_compile(int32_t argc, Janet *argv) { janet_fixarity(argc, 1); JanetPeg *peg = compile_peg(argv[0]); return janet_wrap_abstract(peg); } /* Common data for peg cfunctions */ typedef struct { JanetPeg *peg; PegState s; JanetByteView bytes; JanetByteView repl; int32_t start; } PegCall; /* Initialize state for peg cfunctions */ static PegCall peg_cfun_init(int32_t argc, Janet *argv, int get_replace) { PegCall ret; int32_t min = get_replace ? 3 : 2; janet_arity(argc, get_replace, -1); if (janet_checktype(argv[0], JANET_ABSTRACT) && janet_abstract_type(janet_unwrap_abstract(argv[0])) == &janet_peg_type) { ret.peg = janet_unwrap_abstract(argv[0]); } else { ret.peg = compile_peg(argv[0]); } if (get_replace) { ret.repl = janet_getbytes(argv, 1); ret.bytes = janet_getbytes(argv, 2); } else { ret.bytes = janet_getbytes(argv, 1); } if (argc > min) { ret.start = janet_gethalfrange(argv, min, ret.bytes.len, "offset"); ret.s.extrac = argc - min - 1; ret.s.extrav = janet_tuple_n(argv + min + 1, argc - min - 1); } else { ret.start = 0; ret.s.extrac = 0; ret.s.extrav = NULL; } ret.s.mode = PEG_MODE_NORMAL; ret.s.text_start = ret.bytes.bytes; ret.s.text_end = ret.bytes.bytes + ret.bytes.len; ret.s.depth = JANET_RECURSION_GUARD; ret.s.captures = janet_array(0); ret.s.tagged_captures = janet_array(0); ret.s.scratch = janet_buffer(10); ret.s.tags = janet_buffer(10); ret.s.constants = ret.peg->constants; ret.s.bytecode = ret.peg->bytecode; ret.s.linemap = NULL; ret.s.linemaplen = -1; ret.s.has_backref = ret.peg->has_backref; return ret; } static void peg_call_reset(PegCall *c) { c->s.captures->count = 0; c->s.scratch->count = 0; c->s.tags->count = 0; } static Janet cfun_peg_match(int32_t argc, Janet *argv) { PegCall c = peg_cfun_init(argc, argv, 0); const uint8_t *result = peg_rule(&c.s, c.s.bytecode, c.bytes.bytes + c.start); return result ? janet_wrap_array(c.s.captures) : janet_wrap_nil(); } static Janet cfun_peg_find(int32_t argc, Janet *argv) { PegCall c = peg_cfun_init(argc, argv, 0); for (int32_t i = c.start; i < c.bytes.len; i++) { peg_call_reset(&c); if (peg_rule(&c.s, c.s.bytecode, c.bytes.bytes + i)) return janet_wrap_integer(i); } return janet_wrap_nil(); } static Janet cfun_peg_find_all(int32_t argc, Janet *argv) { PegCall c = peg_cfun_init(argc, argv, 0); JanetArray *ret = janet_array(0); for (int32_t i = c.start; i < c.bytes.len; i++) { peg_call_reset(&c); if (peg_rule(&c.s, c.s.bytecode, c.bytes.bytes + i)) janet_array_push(ret, janet_wrap_integer(i)); } return janet_wrap_array(ret); } static Janet cfun_peg_replace_generic(int32_t argc, Janet *argv, int only_one) { PegCall c = peg_cfun_init(argc, argv, 1); JanetBuffer *ret = janet_buffer(0); int32_t trail = 0; for (int32_t i = c.start; i < c.bytes.len;) { peg_call_reset(&c); const uint8_t *result = peg_rule(&c.s, c.s.bytecode, c.bytes.bytes + i); if (NULL != result) { if (trail < i) { janet_buffer_push_bytes(ret, c.bytes.bytes + trail, (i - trail)); trail = i; } int32_t nexti = (int32_t)(result - c.bytes.bytes); janet_buffer_push_bytes(ret, c.repl.bytes, c.repl.len); trail = nexti; if (nexti == i) nexti++; i = nexti; if (only_one) break; } else { i++; } } if (trail < c.bytes.len) { janet_buffer_push_bytes(ret, c.bytes.bytes + trail, (c.bytes.len - trail)); } return janet_wrap_buffer(ret); } static Janet cfun_peg_replace_all(int32_t argc, Janet *argv) { return cfun_peg_replace_generic(argc, argv, 0); } static Janet cfun_peg_replace(int32_t argc, Janet *argv) { return cfun_peg_replace_generic(argc, argv, 1); } static JanetMethod peg_methods[] = { {"match", cfun_peg_match}, {"find", cfun_peg_find}, {"find-all", cfun_peg_find_all}, {"replace", cfun_peg_replace}, {"replace-all", cfun_peg_replace_all}, {NULL, NULL} }; static int cfun_peg_getter(JanetAbstract a, Janet key, Janet *out) { (void) a; if (!janet_checktype(key, JANET_KEYWORD)) return 0; return janet_getmethod(janet_unwrap_keyword(key), peg_methods, out); } static Janet peg_next(void *p, Janet key) { (void) p; return janet_nextmethod(peg_methods, key); } static const JanetReg peg_cfuns[] = { { "peg/compile", cfun_peg_compile, JDOC("(peg/compile peg)\n\n" "Compiles a peg source data structure into a . This will speed up matching " "if the same peg will be used multiple times. Will also use `(dyn :peg-grammar)` to suppliment " "the grammar of the peg for otherwise undefined peg keywords.") }, { "peg/match", cfun_peg_match, JDOC("(peg/match peg text &opt start & args)\n\n" "Match a Parsing Expression Grammar to a byte string and return an array of captured values. " "Returns nil if text does not match the language defined by peg. The syntax of PEGs is documented on the Janet website.") }, { "peg/find", cfun_peg_find, JDOC("(peg/find peg text &opt start & args)\n\n" "Find first index where the peg matches in text. Returns an integer, or nil if not found.") }, { "peg/find-all", cfun_peg_find_all, JDOC("(peg/find-all peg text &opt start & args)\n\n" "Find all indexes where the peg matches in text. Returns an array of integers.") }, { "peg/replace", cfun_peg_replace, JDOC("(peg/replace peg repl text &opt start & args)\n\n" "Replace first match of peg in text with repl, returning a new buffer. The peg does not need to make captures to do replacement. " "If no matches are found, returns the input string in a new buffer.") }, { "peg/replace-all", cfun_peg_replace_all, JDOC("(peg/replace-all peg repl text &opt start & args)\n\n" "Replace all matches of peg in text with repl, returning a new buffer. The peg does not need to make captures to do replacement.") }, {NULL, NULL, NULL} }; /* Load the peg module */ void janet_lib_peg(JanetTable *env) { janet_core_cfuns(env, NULL, peg_cfuns); janet_register_abstract_type(&janet_peg_type); } #endif /* ifdef JANET_PEG */