263 lines
9.3 KiB
C++
263 lines
9.3 KiB
C++
#pragma once
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#include "eval.hh"
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namespace nix {
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// using C a struct allows us to avoid having to define the special
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// members that using string_view here would implicitly delete.
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struct StringToken {
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const char * p;
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size_t l;
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bool hasIndentation;
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operator std::string_view() const { return {p, l}; }
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};
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struct ParserLocation {
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int first_line, first_column;
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int last_line, last_column;
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// backup to recover from yyless(0)
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int stashed_first_line, stashed_first_column;
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int stashed_last_line, stashed_last_column;
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void stash() {
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stashed_first_line = first_line;
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stashed_first_column = first_column;
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stashed_last_line = last_line;
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stashed_last_column = last_column;
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}
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void unstash() {
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first_line = stashed_first_line;
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first_column = stashed_first_column;
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last_line = stashed_last_line;
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last_column = stashed_last_column;
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}
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};
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struct ParserState {
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EvalState & state;
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SymbolTable & symbols;
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Expr * result;
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SourcePath basePath;
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PosTable::Origin origin;
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void dupAttr(const AttrPath & attrPath, const PosIdx pos, const PosIdx prevPos);
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void dupAttr(Symbol attr, const PosIdx pos, const PosIdx prevPos);
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void addAttr(ExprAttrs * attrs, AttrPath && attrPath, Expr * e, const PosIdx pos);
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Formals * validateFormals(Formals * formals, PosIdx pos = noPos, Symbol arg = {});
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Expr * stripIndentation(const PosIdx pos,
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std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>> && es);
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PosIdx at(const ParserLocation & loc);
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};
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inline void ParserState::dupAttr(const AttrPath & attrPath, const PosIdx pos, const PosIdx prevPos)
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{
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throw ParseError({
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.msg = hintfmt("attribute '%1%' already defined at %2%",
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showAttrPath(state.symbols, attrPath), state.positions[prevPos]),
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.errPos = state.positions[pos]
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});
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}
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inline void ParserState::dupAttr(Symbol attr, const PosIdx pos, const PosIdx prevPos)
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{
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throw ParseError({
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.msg = hintfmt("attribute '%1%' already defined at %2%", state.symbols[attr], state.positions[prevPos]),
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.errPos = state.positions[pos]
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});
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}
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inline void ParserState::addAttr(ExprAttrs * attrs, AttrPath && attrPath, Expr * e, const PosIdx pos)
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{
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AttrPath::iterator i;
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// All attrpaths have at least one attr
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assert(!attrPath.empty());
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// Checking attrPath validity.
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// ===========================
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for (i = attrPath.begin(); i + 1 < attrPath.end(); i++) {
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if (i->symbol) {
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ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
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if (j != attrs->attrs.end()) {
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if (!j->second.inherited) {
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ExprAttrs * attrs2 = dynamic_cast<ExprAttrs *>(j->second.e);
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if (!attrs2) dupAttr(attrPath, pos, j->second.pos);
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attrs = attrs2;
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} else
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dupAttr(attrPath, pos, j->second.pos);
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} else {
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ExprAttrs * nested = new ExprAttrs;
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attrs->attrs[i->symbol] = ExprAttrs::AttrDef(nested, pos);
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attrs = nested;
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}
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} else {
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ExprAttrs *nested = new ExprAttrs;
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attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, nested, pos));
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attrs = nested;
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}
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}
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// Expr insertion.
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// ==========================
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if (i->symbol) {
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ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol);
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if (j != attrs->attrs.end()) {
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// This attr path is already defined. However, if both
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// e and the expr pointed by the attr path are two attribute sets,
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// we want to merge them.
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// Otherwise, throw an error.
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auto ae = dynamic_cast<ExprAttrs *>(e);
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auto jAttrs = dynamic_cast<ExprAttrs *>(j->second.e);
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if (jAttrs && ae) {
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for (auto & ad : ae->attrs) {
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auto j2 = jAttrs->attrs.find(ad.first);
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if (j2 != jAttrs->attrs.end()) // Attr already defined in iAttrs, error.
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dupAttr(ad.first, j2->second.pos, ad.second.pos);
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jAttrs->attrs.emplace(ad.first, ad.second);
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}
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jAttrs->dynamicAttrs.insert(jAttrs->dynamicAttrs.end(), ae->dynamicAttrs.begin(), ae->dynamicAttrs.end());
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} else {
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dupAttr(attrPath, pos, j->second.pos);
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}
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} else {
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// This attr path is not defined. Let's create it.
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attrs->attrs.emplace(i->symbol, ExprAttrs::AttrDef(e, pos));
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e->setName(i->symbol);
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}
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} else {
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attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, e, pos));
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}
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}
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inline Formals * ParserState::validateFormals(Formals * formals, PosIdx pos, Symbol arg)
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{
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std::sort(formals->formals.begin(), formals->formals.end(),
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[] (const auto & a, const auto & b) {
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return std::tie(a.name, a.pos) < std::tie(b.name, b.pos);
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});
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std::optional<std::pair<Symbol, PosIdx>> duplicate;
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for (size_t i = 0; i + 1 < formals->formals.size(); i++) {
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if (formals->formals[i].name != formals->formals[i + 1].name)
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continue;
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std::pair thisDup{formals->formals[i].name, formals->formals[i + 1].pos};
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duplicate = std::min(thisDup, duplicate.value_or(thisDup));
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}
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if (duplicate)
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throw ParseError({
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.msg = hintfmt("duplicate formal function argument '%1%'", symbols[duplicate->first]),
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.errPos = state.positions[duplicate->second]
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});
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if (arg && formals->has(arg))
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throw ParseError({
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.msg = hintfmt("duplicate formal function argument '%1%'", symbols[arg]),
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.errPos = state.positions[pos]
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});
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return formals;
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}
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inline Expr * ParserState::stripIndentation(const PosIdx pos,
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std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>> && es)
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{
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if (es.empty()) return new ExprString("");
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/* Figure out the minimum indentation. Note that by design
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whitespace-only final lines are not taken into account. (So
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the " " in "\n ''" is ignored, but the " " in "\n foo''" is.) */
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bool atStartOfLine = true; /* = seen only whitespace in the current line */
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size_t minIndent = 1000000;
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size_t curIndent = 0;
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for (auto & [i_pos, i] : es) {
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auto * str = std::get_if<StringToken>(&i);
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if (!str || !str->hasIndentation) {
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/* Anti-quotations and escaped characters end the current start-of-line whitespace. */
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if (atStartOfLine) {
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atStartOfLine = false;
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if (curIndent < minIndent) minIndent = curIndent;
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}
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continue;
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}
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for (size_t j = 0; j < str->l; ++j) {
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if (atStartOfLine) {
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if (str->p[j] == ' ')
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curIndent++;
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else if (str->p[j] == '\n') {
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/* Empty line, doesn't influence minimum
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indentation. */
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curIndent = 0;
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} else {
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atStartOfLine = false;
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if (curIndent < minIndent) minIndent = curIndent;
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}
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} else if (str->p[j] == '\n') {
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atStartOfLine = true;
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curIndent = 0;
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}
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}
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}
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/* Strip spaces from each line. */
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auto * es2 = new std::vector<std::pair<PosIdx, Expr *>>;
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atStartOfLine = true;
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size_t curDropped = 0;
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size_t n = es.size();
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auto i = es.begin();
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const auto trimExpr = [&] (Expr * e) {
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atStartOfLine = false;
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curDropped = 0;
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es2->emplace_back(i->first, e);
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};
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const auto trimString = [&] (const StringToken & t) {
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std::string s2;
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for (size_t j = 0; j < t.l; ++j) {
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if (atStartOfLine) {
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if (t.p[j] == ' ') {
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if (curDropped++ >= minIndent)
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s2 += t.p[j];
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}
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else if (t.p[j] == '\n') {
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curDropped = 0;
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s2 += t.p[j];
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} else {
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atStartOfLine = false;
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curDropped = 0;
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s2 += t.p[j];
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}
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} else {
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s2 += t.p[j];
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if (t.p[j] == '\n') atStartOfLine = true;
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}
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}
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/* Remove the last line if it is empty and consists only of
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spaces. */
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if (n == 1) {
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std::string::size_type p = s2.find_last_of('\n');
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if (p != std::string::npos && s2.find_first_not_of(' ', p + 1) == std::string::npos)
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s2 = std::string(s2, 0, p + 1);
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}
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es2->emplace_back(i->first, new ExprString(std::move(s2)));
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};
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for (; i != es.end(); ++i, --n) {
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std::visit(overloaded { trimExpr, trimString }, i->second);
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}
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/* If this is a single string, then don't do a concatenation. */
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if (es2->size() == 1 && dynamic_cast<ExprString *>((*es2)[0].second)) {
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auto *const result = (*es2)[0].second;
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delete es2;
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return result;
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}
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return new ExprConcatStrings(pos, true, es2);
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}
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inline PosIdx ParserState::at(const ParserLocation & loc)
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{
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return state.positions.add(origin, loc.first_line, loc.first_column);
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}
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}
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