--- /dev/null
+#ifndef FORTRAN_COOKED_TOKENS_H_
+#define FORTRAN_COOKED_TOKENS_H_
+
+// These parsers are driven by the Fortran grammar (grammar.h) to consume
+// the cooked character stream from cookedNextChar (cooked-chars.h) and
+// partition it into a context-sensitive token stream.
+
+#include "basic-parsers.h"
+#include "cooked-chars.h"
+#include "idioms.h"
+#include "position.h"
+#include <cctype>
+#include <cstring>
+#include <functional>
+#include <limits>
+#include <list>
+#include <optional>
+#include <string>
+
+namespace Fortran {
+
+class CharPredicateGuardParser {
+ public:
+ using resultType = char;
+ constexpr CharPredicateGuardParser(const CharPredicateGuardParser &)
+ = default;
+ constexpr CharPredicateGuardParser(bool (*f)(char), const char *msg)
+ : predicate_{f}, message_{msg} {}
+ std::optional<char> Parse(ParseState *state) const {
+ Position at{state->position()};
+ if (std::optional<char> result{cookedNextChar.Parse(state)}) {
+ if (predicate_(*result)) {
+ return result;
+ }
+ }
+ state->messages()->Add(Message{at, message_, state->context()});
+ return {};
+ }
+ private:
+ bool (*const predicate_)(char);
+ const char *const message_;
+};
+
+static inline constexpr bool IsDecimalDigit(char ch) {
+ return isdigit(ch);
+}
+
+static inline constexpr bool IsOctalDigit(char ch) {
+ return ch >= '0' && ch <= '7';
+}
+
+static inline constexpr bool IsHexadecimalDigit(char ch) {
+ return isxdigit(ch);
+}
+
+static inline constexpr bool IsLetter(char ch) {
+ return isalpha(ch);
+}
+
+static inline constexpr char ToLower(char &&ch) {
+ return tolower(ch);
+}
+
+constexpr CharPredicateGuardParser digit{IsDecimalDigit, "expected digit"};
+
+constexpr auto letter =
+ applyFunction(ToLower,
+ CharPredicateGuardParser{IsLetter, "expected letter"});
+
+template<char good>
+class CharMatch {
+ public:
+ using resultType = char;
+ constexpr CharMatch() {}
+ static std::optional<char> Parse(ParseState *state) {
+ Position at{state->position()};
+ std::optional<char> result{cookedNextChar.Parse(state)};
+ if (result && *result != good) {
+ result.reset();
+ }
+ if (!result) {
+ state->messages()->Add(Message{at, good, state->context()});
+ }
+ return {result};
+ }
+};
+
+constexpr struct Space {
+ using resultType = Success;
+ constexpr Space() {}
+ static std::optional<Success> Parse(ParseState *state) {
+ std::optional<char> ch{cookedNextChar.Parse(state)};
+ if (ch) {
+ if (ch == ' ' || ch == '\t') {
+ return {Success{}};
+ }
+ }
+ return {};
+ }
+} space;
+
+constexpr auto spaces = skipMany(space);
+
+class TokenStringMatch {
+ public:
+ using resultType = Success;
+ constexpr TokenStringMatch(const TokenStringMatch &) = default;
+ constexpr TokenStringMatch(const char *str, size_t n)
+ : str_{str}, length_{n} {}
+ constexpr TokenStringMatch(const char *str) : str_{str} {}
+ std::optional<Success> Parse(ParseState *state) const {
+ Position at{state->position()};
+ if (!spaces.Parse(state)) {
+ return {};
+ }
+ const char *p{str_};
+ std::optional<char> ch; // initially empty
+ for (size_t j{0}; j < length_ && *p != '\0'; ++j, ++p) {
+ const auto spaceSkipping{*p == ' '};
+ if (spaceSkipping) {
+ if (j + 1 == length_ || p[1] == ' ' || p[1] == '\0') {
+ continue; // redundant; ignore
+ }
+ }
+ if (!ch && !(ch = cookedNextChar.Parse(state))) {
+ return {};
+ }
+ if (spaceSkipping) {
+ // medial space: 0 or more spaces/tabs accepted, none required
+ while (*ch == ' ' || *ch == '\t') {
+ if (!(ch = cookedNextChar.Parse(state))) {
+ return {};
+ }
+ }
+ // ch remains full for next iteration
+ } else if (*ch == tolower(*p)) {
+ ch.reset();
+ } else {
+ state->messages()->Add(Message{at, "expected '"s + str_ + '\'',
+ state->context()});
+ return {};
+ }
+ }
+ return spaces.Parse(state);
+ }
+ private:
+ const char *const str_;
+ const size_t length_{std::numeric_limits<size_t>::max()};
+};
+
+constexpr TokenStringMatch operator""_tok(const char str[], size_t n) {
+ return TokenStringMatch{str, n};
+}
+
+template<class PA, std::enable_if_t<std::is_class<PA>::value, int> = 0>
+inline constexpr SequenceParser<TokenStringMatch, PA>
+operator>>(const char *str, const PA &p) {
+ return SequenceParser<TokenStringMatch, PA>{TokenStringMatch{str}, p};
+}
+
+template<class PA, std::enable_if_t<std::is_class<PA>::value, int> = 0>
+inline constexpr InvertedSequenceParser<PA, TokenStringMatch>
+operator/(const PA &p, const char *str) {
+ return InvertedSequenceParser<PA, TokenStringMatch>{p, TokenStringMatch{str}};
+}
+
+template<class PA>
+inline constexpr SequenceParser<TokenStringMatch,
+ InvertedSequenceParser<PA, TokenStringMatch>>
+parenthesized(const PA &p) {
+ return "(" >> p / ")";
+}
+
+template<class PA>
+inline constexpr SequenceParser<TokenStringMatch,
+ InvertedSequenceParser<PA, TokenStringMatch>>
+bracketed(const PA &p) {
+ return "[" >> p / "]";
+}
+
+static inline int HexadecimalDigitValue(char ch) {
+ if (IsDecimalDigit(ch)) {
+ return ch - '0';
+ }
+ return toupper(ch) - 'A' + 10;
+}
+
+// Quoted character literal constants.
+struct CharLiteralChar {
+ struct Result {
+ Result(char c, bool esc) : ch{c}, wasEscaped{esc} {}
+ static Result Bare(char c) { return Result{c, false}; }
+ static Result Escaped(char c) { return Result{c, true}; }
+ char ch;
+ bool wasEscaped;
+ };
+ using resultType = Result;
+ static std::optional<Result> Parse(ParseState *state) {
+ Position at{state->position()};
+ std::optional<char> och{cookedNextChar.Parse(state)};
+ if (!och.has_value()) {
+ return {};
+ }
+ char ch{*och};
+ if (ch == '\n') {
+ state->messages()->Add(Message{at, "unclosed character constant",
+ state->context()});
+ return {};
+ }
+ if (ch != '\\' || !state->enableBackslashEscapesInCharLiterals()) {
+ return {Result::Bare(ch)};
+ }
+ if (!(och = cookedNextChar.Parse(state)).has_value()) {
+ return {};
+ }
+ switch ((ch = *och)) {
+ case 'a': return {Result::Escaped('\a')};
+ case 'b': return {Result::Escaped('\b')};
+ case 'f': return {Result::Escaped('\f')};
+ case 'n': return {Result::Escaped('\n')};
+ case 'r': return {Result::Escaped('\r')};
+ case 't': return {Result::Escaped('\t')};
+ case 'v': return {Result::Escaped('\v')};
+ case '"':
+ case '\'':
+ case '\\':
+ return {Result::Escaped(ch)};
+ case '\n':
+ state->messages()->Add(Message{at, "unclosed character constant",
+ state->context()});
+ return {};
+ default:
+ if (IsOctalDigit(ch)) {
+ ch -= '0';
+ for (int j = (ch > 3 ? 1 : 2); j-- > 0;) {
+ static constexpr auto octalDigit =
+ attempt(CharPredicateGuardParser{IsOctalDigit,
+ "expected octal digit"});
+ if ((och = octalDigit.Parse(state)).has_value()) {
+ ch = 8 * ch + *och - '0';
+ }
+ }
+ } else if (ch == 'x' || ch == 'X') {
+ ch = 0;
+ for (int j = 0; j++ < 2;) {
+ static constexpr auto hexDigit =
+ attempt(CharPredicateGuardParser{IsHexadecimalDigit,
+ "expected hexadecimal digit"});
+ if ((och = hexDigit.Parse(state)).has_value()) {
+ ch = 16 * ch + HexadecimalDigitValue(*och);
+ }
+ }
+ } else {
+ state->messages()->Add(Message{at, "bad escaped character",
+ state->context()});
+ }
+ return {Result::Escaped(ch)};
+ }
+ }
+};
+
+template<char quote>
+struct CharLiteral {
+ using resultType = std::string;
+ static std::optional<std::string> Parse(ParseState *state) {
+ std::string str;
+ CHECK(!state->set_inCharLiteral(true));
+ static constexpr auto nextch = attempt(CharLiteralChar{});
+ while (std::optional<CharLiteralChar::Result> ch{nextch.Parse(state)}) {
+ if (ch->ch == quote && !ch->wasEscaped) {
+ static constexpr auto doubled = attempt(CharMatch<quote>{});
+ if (!doubled.Parse(state).has_value()) {
+ state->set_inCharLiteral(false);
+ return {str};
+ }
+ }
+ str += ch->ch;
+ }
+ return {};
+ }
+};
+
+// Parse "BOZ" binary literal quoted constants.
+// As extensions, support X as an alternate hexadecimal marker, and allow
+// BOZX markers to appear as synonyms.
+struct BOZLiteral {
+ using resultType = std::uint64_t;
+ static std::optional<std::uint64_t> Parse(ParseState *state) {
+ std::optional<int> shift;
+ auto baseChar = [&shift](char ch) -> bool {
+ switch (toupper(ch)) {
+ case 'B': shift = 1; return true;
+ case 'O': shift = 3; return true;
+ case 'Z': shift = 4; return true;
+ case 'X': shift = 4; return true;
+ default: return false;
+ }
+ };
+
+ if (!spaces.Parse(state)) {
+ return {};
+ }
+
+ auto ch = cookedNextChar.Parse(state);
+ if (!ch) {
+ return {};
+ }
+ if (toupper(*ch) == 'X' && state->strictConformance()) {
+ return {};
+ }
+ if (baseChar(*ch) && !(ch = cookedNextChar.Parse(state))) {
+ return {};
+ }
+
+ char quote = *ch;
+ if (quote != '\'' && quote != '"') {
+ return {};
+ }
+
+ Position at{state->position()};
+ std::string content;
+ while (true) {
+ if (!(ch = cookedNextChar.Parse(state))) {
+ return {};
+ }
+ if (*ch == quote) {
+ break;
+ }
+ if (!isxdigit(*ch)) {
+ return {};
+ }
+ content += *ch;
+ }
+
+ if (!shift && !state->strictConformance()) {
+ // extension: base allowed to appear as suffix
+ if (!(ch = cookedNextChar.Parse(state)) || !baseChar(*ch)) {
+ return {};
+ }
+ }
+
+ if (content.empty()) {
+ state->messages()->Add(Message{at, "no digit in BOZ literal",
+ state->context()});
+ return {};
+ }
+
+ std::uint64_t value{0};
+ for (auto digit : content) {
+ digit = HexadecimalDigitValue(digit);
+ if ((digit >> *shift) > 0) {
+ state->messages()->Add(Message{at, "bad digit in BOZ literal",
+ state->context()});
+ return {};
+ }
+ std::uint64_t was{value};
+ value <<= *shift;
+ if ((value >> *shift) != was) {
+ state->messages()->Add(Message{at, "excessive digits in BOZ literal",
+ state->context()});
+ return {};
+ }
+ value |= digit;
+ }
+ return {value};
+ }
+};
+
+// Unsigned decimal digit string; no space skipping
+struct DigitString {
+ using resultType = std::uint64_t;
+ static std::optional<std::uint64_t> Parse(ParseState *state) {
+ static constexpr auto getDigit = attempt(digit);
+ Position at{state->position()};
+ std::optional<char> firstDigit{getDigit.Parse(state)};
+ if (!firstDigit) {
+ return {};
+ }
+ std::uint64_t value = *firstDigit - '0';
+ bool overflow{false};
+ while (auto nextDigit{getDigit.Parse(state)}) {
+ if (value > std::numeric_limits<std::uint64_t>::max() / 10) {
+ overflow = true;
+ }
+ value *= 10;
+ int digitValue = *nextDigit - '0';
+ if (value > std::numeric_limits<std::uint64_t>::max() - digitValue) {
+ overflow = true;
+ }
+ value += digitValue;
+ }
+ if (overflow) {
+ state->messages()->Add(Message{at, "overflow in decimal literal",
+ state->context()});
+ }
+ return {value};
+ }
+};
+
+// Legacy feature: Hollerith literal constants
+struct HollerithLiteral {
+ using resultType = std::string;
+ static std::optional<std::string> Parse(ParseState *state) {
+ if (!spaces.Parse(state)) {
+ return {};
+ }
+ Position at{state->position()};
+ std::optional<std::uint64_t> charCount{DigitString{}.Parse(state)};
+ if (!charCount || *charCount < 1) {
+ return {};
+ }
+ std::optional<char> h {letter.Parse(state)};
+ if (!h || (*h != 'h' && *h != 'H')) {
+ return {};
+ }
+ std::string content;
+ CHECK(!state->set_inCharLiteral(true));
+ for (auto j = *charCount; j-- > 0; ) {
+ std::optional<char> ch{cookedNextChar.Parse(state)};
+ if (!ch || !isprint(*ch)) {
+ state->messages()->Add(Message{at,
+ "insufficient or bad characters in Hollerith",
+ state->context()});
+ state->set_inCharLiteral(false);
+ return {};
+ }
+ content += *ch;
+ }
+ state->set_inCharLiteral(false);
+ return {content};
+ }
+};
+
+// A common idiom in the Fortran grammar is an optional item (usually
+// a nonempty comma-separated list) that, if present, must follow a comma
+// and precede a doubled colon. When the item is absent, the comma must
+// not appear, and the doubled colons are optional.
+// [[, xyz] ::] is optionalBeforeColons(xyz)
+// [[, xyz]... ::] is optionalBeforeColons(nonemptyList(xyz))
+template<typename PA>
+inline constexpr auto optionalBeforeColons(const PA &p) {
+ return "," >> p / "::" ||
+ "::" >> construct<typename PA::resultType>{} ||
+ !","_tok >> construct<typename PA::resultType>{};
+}
+} // namespace Fortran
+#endif // FORTRAN_COOKED_TOKENS_H_
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