ad7125ffb0
Original-commit: flang-compiler/f18@8c7f51aa87
502 lines
12 KiB
C++
502 lines
12 KiB
C++
#include "prescan.h"
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#include "char-buffer.h"
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#include "idioms.h"
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#include "source.h"
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#include <cctype>
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#include <cstring>
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#include <utility>
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#include <vector>
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namespace Fortran {
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CharBuffer Prescanner::Prescan(const SourceFile &source) {
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sourceFile_ = &source;
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lineStart_ = source.content();
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limit_ = lineStart_ + source.bytes();
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CharBuffer out;
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TokenSequence tokens, preprocessed;
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while (lineStart_ < limit_) {
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if (CommentLinesAndPreprocessorDirectives() &&
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lineStart_ >= limit_) {
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break;
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}
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BeginSourceLineAndAdvance();
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if (inFixedForm_) {
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LabelField(&tokens);
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} else {
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SkipSpaces();
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}
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while (NextToken(&tokens)) {
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}
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if (preprocessor_.MacroReplacement(tokens, &preprocessed)) {
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preprocessed.AddChar('\n');
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preprocessed.EndToken();
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if (IsFixedFormCommentLine(preprocessed.data()) ||
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IsFreeFormComment(preprocessed.data())) {
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++newlineDebt_;
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} else {
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preprocessed.pop_back(); // clip the newline added above
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preprocessed.EmitWithCaseConversion(&out);
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}
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preprocessed.clear();
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} else {
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tokens.EmitWithCaseConversion(&out);
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}
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tokens.clear();
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out.Put('\n');
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PayNewlineDebt(&out);
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}
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PayNewlineDebt(&out);
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sourceFile_ = nullptr;
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return std::move(out);
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}
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std::optional<TokenSequence> Prescanner::NextTokenizedLine() {
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if (lineStart_ >= limit_) {
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return {};
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}
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bool wasInPreprocessorDirective{inPreprocessorDirective_};
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auto saveAt = at_;
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auto saveAtPosition = atPosition_;
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inPreprocessorDirective_ = true;
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BeginSourceLineAndAdvance();
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TokenSequence tokens;
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while (NextToken(&tokens)) {
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}
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inPreprocessorDirective_ = wasInPreprocessorDirective;
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at_ = saveAt;
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atPosition_ = saveAtPosition;
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return {std::move(tokens)};
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}
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void Prescanner::NextLine() {
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void *vstart{static_cast<void *>(const_cast<char *>(lineStart_))};
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void *v{std::memchr(vstart, '\n', limit_ - lineStart_)};
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if (v == nullptr) {
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lineStart_ = limit_;
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} else {
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const char *nl{const_cast<const char *>(static_cast<char *>(v))};
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lineStart_ = nl + 1;
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}
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lineStartPosition_.AdvanceLine();
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}
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void Prescanner::LabelField(TokenSequence *token) {
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int outCol{1};
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for (; *at_ != '\n' && atPosition_.column() <= 6; ++at_) {
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if (*at_ == '\t') {
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++at_;
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atPosition_.set_column(7);
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break;
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}
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if (*at_ != ' ' &&
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(*at_ != '0' ||
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atPosition_.column() != 6)) { // '0' in column 6 becomes space
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token->AddChar(*at_);
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++outCol;
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}
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atPosition_.AdvanceColumn();
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}
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if (outCol > 1) {
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token->EndToken();
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}
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if (outCol < 7) {
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for (; outCol < 7; ++outCol) {
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token->AddChar(' ');
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}
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token->EndToken();
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}
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}
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void Prescanner::NextChar() {
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// CHECK(*at_ != '\n');
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++at_;
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atPosition_.AdvanceColumn();
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if (inPreprocessorDirective_) {
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while (*at_ == '/' && at_[1] == '*') {
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char star{' '}, slash{' '};
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at_ += 2;
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atPosition_.set_column(atPosition_.column() + 2);
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while ((*at_ != '\n' || slash == '\\') && (star != '*' || slash != '/')) {
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star = slash;
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slash = *at_++;
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atPosition_.AdvanceColumn();
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}
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}
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while (*at_ == '\\' && at_ + 2 < limit_ && at_[1] == '\n') {
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BeginSourceLineAndAdvance();
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++newlineDebt_;
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}
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} else {
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if ((inFixedForm_ && atPosition_.column() > fixedFormColumnLimit_ &&
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!tabInCurrentLine_) ||
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(*at_ == '!' && !inCharLiteral_)) {
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while (*at_ != '\n') {
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++at_;
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}
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}
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while (*at_ == '\n' || *at_ == '&') {
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if ((inFixedForm_ && !FixedFormContinuation()) ||
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(!inFixedForm_ && !FreeFormContinuation())) {
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return;
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}
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}
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if (*at_ == '\t') {
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tabInCurrentLine_ = true;
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}
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}
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}
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void Prescanner::SkipSpaces() {
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while (*at_ == ' ' || *at_ == '\t') {
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NextChar();
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}
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}
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static inline bool IsNameChar(char ch) {
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return isalnum(ch) || ch == '_' || ch == '$' || ch == '@';
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}
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bool Prescanner::NextToken(TokenSequence *tokens) {
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if (inFixedForm_) {
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SkipSpaces();
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} else if (*at_ == ' ' || *at_ == '\t') {
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NextChar();
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SkipSpaces();
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if (*at_ != '\n') {
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tokens->AddChar(' ');
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tokens->EndToken();
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return true;
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}
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}
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if (*at_ == '\n') {
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return false;
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}
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if (*at_ == '\'' || *at_ == '"') {
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QuotedCharacterLiteral(tokens);
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preventHollerith_ = false;
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} else if (isdigit(*at_)) {
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int n{0};
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static constexpr int maxHollerith = 256 * (132-6);
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do {
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if (n < maxHollerith) {
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n = 10 * n + *at_ - '0';
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}
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EmitCharAndAdvance(tokens, *at_);
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if (inFixedForm_) {
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SkipSpaces();
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}
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} while (isdigit(*at_));
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if ((*at_ == 'h' || *at_ == 'H') &&
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n > 0 && n < maxHollerith &&
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!preventHollerith_) {
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EmitCharAndAdvance(tokens, 'h');
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inCharLiteral_ = true;
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while (n-- > 0) {
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if (PadOutCharacterLiteral()) {
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tokens->AddChar(' ');
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} else {
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if (*at_ == '\n') {
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break; // TODO error
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}
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EmitCharAndAdvance(tokens, *at_);
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}
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}
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inCharLiteral_ = false;
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} else if (*at_ == '.') {
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while (isdigit(EmitCharAndAdvance(tokens, *at_))) {
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}
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ExponentAndKind(tokens);
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} else if (ExponentAndKind(tokens)) {
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} else if (isalpha(*at_)) {
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// Handles FORMAT(3I9HHOLLERITH) by skipping over the first I so that
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// we don't misrecognize I9HOLLERITH as an identifier in the next case.
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EmitCharAndAdvance(tokens, *at_);
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}
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preventHollerith_ = false;
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} else if (*at_ == '.') {
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if (isdigit(EmitCharAndAdvance(tokens, '.'))) {
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while (isdigit(EmitCharAndAdvance(tokens, *at_))) {
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}
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ExponentAndKind(tokens);
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}
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preventHollerith_ = false;
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} else if (IsNameChar(*at_)) {
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while (IsNameChar(EmitCharAndAdvance(tokens, *at_))) {
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}
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if (*at_ == '\'' || *at_ == '"') {
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QuotedCharacterLiteral(tokens);
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}
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preventHollerith_ = false;
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} else if (*at_ == '*') {
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if (EmitCharAndAdvance(tokens, '*') == '*') {
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EmitCharAndAdvance(tokens, '*');
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} else {
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preventHollerith_ = true; // ambiguity: CHARACTER*2H
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}
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} else {
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char ch{*at_};
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if (ch == '(' || ch == '[') {
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++delimiterNesting_;
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} else if ((ch == ')' || ch == ']') && delimiterNesting_ > 0) {
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--delimiterNesting_;
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}
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char nch{EmitCharAndAdvance(tokens, ch)};
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preventHollerith_ = false;
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if ((nch == '=' &&
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(ch == '<' || ch == '>' || ch == '/' || ch == '=' ||
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ch == '!')) ||
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(ch == nch &&
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(ch == '/' || ch == ':' || ch == '*' ||
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ch == '#' || ch == '&' || ch == '|' || ch == '<' || ch == '>')) ||
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(ch == '=' && nch == '>')) {
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// token comprises two characters
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EmitCharAndAdvance(tokens, nch);
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}
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}
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tokens->EndToken();
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return true;
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}
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bool Prescanner::ExponentAndKind(TokenSequence *tokens) {
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char ed = tolower(*at_);
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if (ed != 'e' && ed != 'd') {
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return false;
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}
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EmitCharAndAdvance(tokens, ed);
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if (*at_ == '+' || *at_ == '-') {
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EmitCharAndAdvance(tokens, *at_);
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}
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while (isdigit(*at_)) {
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EmitCharAndAdvance(tokens, *at_);
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}
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if (*at_ == '_') {
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while (IsNameChar(EmitCharAndAdvance(tokens, *at_))) {
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}
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}
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return true;
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}
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void Prescanner::QuotedCharacterLiteral(TokenSequence *tokens) {
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char quote{*at_};
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inCharLiteral_ = true;
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do {
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EmitCharAndAdvance(tokens, *at_);
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while (PadOutCharacterLiteral()) {
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tokens->AddChar(' ');
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}
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if (*at_ == '\\' && enableBackslashEscapesInCharLiterals_) {
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EmitCharAndAdvance(tokens, '\\');
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while (PadOutCharacterLiteral()) {
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tokens->AddChar(' ');
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}
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} else if (*at_ == quote) {
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// A doubled quote mark becomes a single instance of the quote character
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// in the literal later.
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EmitCharAndAdvance(tokens, quote);
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if (inFixedForm_) {
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SkipSpaces();
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}
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if (*at_ != quote) {
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break;
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}
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}
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} while (*at_ != '\n');
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inCharLiteral_ = false;
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}
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bool Prescanner::PadOutCharacterLiteral() {
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if (inFixedForm_ &&
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!tabInCurrentLine_ &&
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*at_ == '\n' &&
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atPosition_.column() < fixedFormColumnLimit_) {
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atPosition_.AdvanceColumn();
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return true;
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}
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return false;
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}
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bool Prescanner::IsFixedFormCommentLine(const char *start) {
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if (start >= limit_ || !inFixedForm_) {
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return false;
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}
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const char *p{start};
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char ch{*p};
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if (ch == '*' || ch == 'C' || ch == 'c' ||
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ch == '%' || // VAX %list, %eject, &c.
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((ch == 'D' || ch == 'd') && !enableOldDebugLines_)) {
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return true;
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}
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bool anyTabs{false};
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while (true) {
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ch = *p;
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if (ch == ' ') {
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++p;
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} else if (ch == '\t') {
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anyTabs = true;
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++p;
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} else if (ch == '0' && !anyTabs && p == start + 5) {
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++p; // 0 in column 6 must treated as a space
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} else {
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break;
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}
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}
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if (!anyTabs && p >= start + fixedFormColumnLimit_) {
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return true;
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}
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if (*p == '!' && !inCharLiteral_ && (anyTabs || p != start + 5)) {
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return true;
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}
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return *p == '\n';
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}
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bool Prescanner::IsFreeFormComment(const char *p) {
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if (p >= limit_ || inFixedForm_) {
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return false;
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}
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while (*p == ' ' || *p == '\t') {
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++p;
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}
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return *p == '!' || *p == '\n';
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}
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bool Prescanner::IsPreprocessorDirectiveLine(const char *start) {
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const char *p{start};
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if (p >= limit_ || inPreprocessorDirective_) {
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return false;
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}
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for (; *p == ' '; ++p) {
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}
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if (*p == '#') {
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return !inFixedForm_ || p != start + 5;
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}
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for (; *p == ' ' || *p == '\t'; ++p) {
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}
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return *p == '#';
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}
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bool Prescanner::CommentLines() {
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bool any{false};
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while (lineStart_ < limit_) {
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if (IsFixedFormCommentLine(lineStart_) ||
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IsFreeFormComment(lineStart_)) {
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NextLine();
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++newlineDebt_;
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any = true;
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} else {
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break;
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}
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}
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return any;
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}
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bool Prescanner::CommentLinesAndPreprocessorDirectives() {
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bool any{false};
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while (lineStart_ < limit_) {
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if (IsFixedFormCommentLine(lineStart_) ||
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IsFreeFormComment(lineStart_)) {
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NextLine();
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} else if (IsPreprocessorDirectiveLine(lineStart_)) {
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auto here = lineStartPosition_;
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if (std::optional<TokenSequence> tokens{NextTokenizedLine()}) {
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std::string err{preprocessor_.Directive(*tokens)};
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if (!err.empty()) {
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*error_ << here << ' ' << err << '\n';
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}
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}
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} else {
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break;
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}
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++newlineDebt_;
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any = true;
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}
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return any;
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}
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const char *Prescanner::FixedFormContinuationLine() {
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const char *p{lineStart_};
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if (p >= limit_) {
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return nullptr;
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}
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tabInCurrentLine_ = false;
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if (*p == '&') {
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return p + 1; // extension
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}
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if (*p == '\t' && p[1] >= '1' && p[1] <= '9') {
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tabInCurrentLine_ = true;
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return p + 2; // VAX extension
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}
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if (p[0] == ' ' && p[1] == ' ' && p[2] == ' ' &&
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p[3] == ' ' && p[4] == ' ') {
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char col6{p[5]};
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if (col6 != '\n' && col6 != '\t' && col6 != ' ' && col6 != '0') {
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return p + 6;
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}
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}
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if (delimiterNesting_ > 0) {
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return p;
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}
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return nullptr; // not a continuation line
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}
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bool Prescanner::FixedFormContinuation() {
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CommentLines();
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const char *cont{FixedFormContinuationLine()};
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if (cont == nullptr) {
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return false;
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}
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BeginSourceLine(cont);
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atPosition_.set_column(7);
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++newlineDebt_;
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NextLine();
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return true;
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}
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bool Prescanner::FreeFormContinuation() {
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while (*at_ == ' ' || *at_ == '\t') {
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++at_;
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}
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const char *p{at_};
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bool ampersand{*p == '&'};
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if (ampersand) {
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for (++p; *p == ' ' || *p == '\t'; ++p) {
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}
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}
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if (*p != '\n' && (inCharLiteral_ || *p != '!')) {
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return false;
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}
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CommentLines();
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p = lineStart_;
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if (p >= limit_) {
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return false;
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}
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int column{1};
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for (; *p == ' ' || *p == '\t'; ++p) {
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++column;
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}
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if (*p == '&') {
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++p;
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++column;
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} else if (ampersand || delimiterNesting_ > 0) {
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if (p > lineStart_) {
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--p;
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--column;
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}
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} else {
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return false; // not a continuation
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}
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at_ = p;
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(atPosition_ = lineStartPosition_).set_column(column);
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tabInCurrentLine_ = false;
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++newlineDebt_;
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NextLine();
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return true;
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}
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void Prescanner::PayNewlineDebt(CharBuffer *out) {
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for (; newlineDebt_ > 0; --newlineDebt_) {
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out->Put('\n');
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}
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}
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} // namespace Fortran
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