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Diffstat (limited to 'src/libexpr/parser/state.hh')
| -rw-r--r-- | src/libexpr/parser/state.hh | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/src/libexpr/parser/state.hh b/src/libexpr/parser/state.hh new file mode 100644 index 000000000..f5a0428d7 --- /dev/null +++ b/src/libexpr/parser/state.hh @@ -0,0 +1,259 @@ +#pragma once +///@file + +#include "eval.hh" + +namespace nix::parser { + +struct StringToken +{ + std::string_view s; + bool hasIndentation; + operator std::string_view() const { return s; } +}; + +struct State +{ + SymbolTable & symbols; + PosTable & positions; + SourcePath basePath; + PosTable::Origin origin; + const Expr::AstSymbols & s; + + void dupAttr(const AttrPath & attrPath, const PosIdx pos, const PosIdx prevPos); + void dupAttr(Symbol attr, const PosIdx pos, const PosIdx prevPos); + void addAttr(ExprAttrs * attrs, AttrPath && attrPath, std::unique_ptr<Expr> e, const PosIdx pos); + std::unique_ptr<Formals> validateFormals(std::unique_ptr<Formals> formals, PosIdx pos = noPos, Symbol arg = {}); + std::unique_ptr<Expr> stripIndentation(const PosIdx pos, + std::vector<std::pair<PosIdx, std::variant<std::unique_ptr<Expr>, StringToken>>> && es); + + // lazy positioning means we don't get byte offsets directly, in.position() would work + // but also requires line and column (which is expensive) + PosIdx at(const auto & in) + { + return positions.add(origin, in.begin() - in.input().begin()); + } + + PosIdx atEnd(const auto & in) + { + return positions.add(origin, in.end() - in.input().begin()); + } +}; + +inline void State::dupAttr(const AttrPath & attrPath, const PosIdx pos, const PosIdx prevPos) +{ + throw ParseError({ + .msg = HintFmt("attribute '%1%' already defined at %2%", + showAttrPath(symbols, attrPath), positions[prevPos]), + .pos = positions[pos] + }); +} + +inline void State::dupAttr(Symbol attr, const PosIdx pos, const PosIdx prevPos) +{ + throw ParseError({ + .msg = HintFmt("attribute '%1%' already defined at %2%", symbols[attr], positions[prevPos]), + .pos = positions[pos] + }); +} + +inline void State::addAttr(ExprAttrs * attrs, AttrPath && attrPath, std::unique_ptr<Expr> e, const PosIdx pos) +{ + AttrPath::iterator i; + // All attrpaths have at least one attr + assert(!attrPath.empty()); + // Checking attrPath validity. + // =========================== + for (i = attrPath.begin(); i + 1 < attrPath.end(); i++) { + if (i->symbol) { + ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol); + if (j != attrs->attrs.end()) { + if (j->second.kind != ExprAttrs::AttrDef::Kind::Inherited) { + ExprAttrs * attrs2 = dynamic_cast<ExprAttrs *>(j->second.e.get()); + if (!attrs2) { + attrPath.erase(i + 1, attrPath.end()); + dupAttr(attrPath, pos, j->second.pos); + } + attrs = attrs2; + } else { + attrPath.erase(i + 1, attrPath.end()); + dupAttr(attrPath, pos, j->second.pos); + } + } else { + auto next = attrs->attrs.emplace(std::piecewise_construct, + std::tuple(i->symbol), + std::tuple(std::make_unique<ExprAttrs>(), pos)); + attrs = static_cast<ExprAttrs *>(next.first->second.e.get()); + } + } else { + auto & next = attrs->dynamicAttrs.emplace_back(std::move(i->expr), std::make_unique<ExprAttrs>(), pos); + attrs = static_cast<ExprAttrs *>(next.valueExpr.get()); + } + } + // Expr insertion. + // ========================== + if (i->symbol) { + ExprAttrs::AttrDefs::iterator j = attrs->attrs.find(i->symbol); + if (j != attrs->attrs.end()) { + // This attr path is already defined. However, if both + // e and the expr pointed by the attr path are two attribute sets, + // we want to merge them. + // Otherwise, throw an error. + auto * ae = dynamic_cast<ExprAttrs *>(e.get()); + auto * jAttrs = dynamic_cast<ExprAttrs *>(j->second.e.get()); + if (jAttrs && ae) { + if (ae->inheritFromExprs && !jAttrs->inheritFromExprs) + jAttrs->inheritFromExprs = std::make_unique<std::vector<std::unique_ptr<Expr>>>(); + for (auto & ad : ae->attrs) { + auto j2 = jAttrs->attrs.find(ad.first); + if (j2 != jAttrs->attrs.end()) // Attr already defined in iAttrs, error. + return dupAttr(ad.first, j2->second.pos, ad.second.pos); + if (ad.second.kind == ExprAttrs::AttrDef::Kind::InheritedFrom) { + auto & sel = dynamic_cast<ExprSelect &>(*ad.second.e); + auto & from = dynamic_cast<ExprInheritFrom &>(*sel.e); + from.displ += jAttrs->inheritFromExprs->size(); + } + jAttrs->attrs.emplace(ad.first, std::move(ad.second)); + } + std::ranges::move(ae->dynamicAttrs, std::back_inserter(jAttrs->dynamicAttrs)); + if (ae->inheritFromExprs) + std::ranges::move(*ae->inheritFromExprs, std::back_inserter(*jAttrs->inheritFromExprs)); + } else { + dupAttr(attrPath, pos, j->second.pos); + } + } else { + // This attr path is not defined. Let's create it. + e->setName(i->symbol); + attrs->attrs.emplace(std::piecewise_construct, + std::tuple(i->symbol), + std::tuple(std::move(e), pos)); + } + } else { + attrs->dynamicAttrs.emplace_back(std::move(i->expr), std::move(e), pos); + } +} + +inline std::unique_ptr<Formals> State::validateFormals(std::unique_ptr<Formals> formals, PosIdx pos, Symbol arg) +{ + std::sort(formals->formals.begin(), formals->formals.end(), + [] (const auto & a, const auto & b) { + return std::tie(a.name, a.pos) < std::tie(b.name, b.pos); + }); + + std::optional<std::pair<Symbol, PosIdx>> duplicate; + for (size_t i = 0; i + 1 < formals->formals.size(); i++) { + if (formals->formals[i].name != formals->formals[i + 1].name) + continue; + std::pair thisDup{formals->formals[i].name, formals->formals[i + 1].pos}; + duplicate = std::min(thisDup, duplicate.value_or(thisDup)); + } + if (duplicate) + throw ParseError({ + .msg = HintFmt("duplicate formal function argument '%1%'", symbols[duplicate->first]), + .pos = positions[duplicate->second] + }); + + if (arg && formals->has(arg)) + throw ParseError({ + .msg = HintFmt("duplicate formal function argument '%1%'", symbols[arg]), + .pos = positions[pos] + }); + + return formals; +} + +inline std::unique_ptr<Expr> State::stripIndentation(const PosIdx pos, + std::vector<std::pair<PosIdx, std::variant<std::unique_ptr<Expr>, StringToken>>> && es) +{ + if (es.empty()) return std::make_unique<ExprString>(""); + + /* Figure out the minimum indentation. Note that by design + whitespace-only final lines are not taken into account. (So + the " " in "\n ''" is ignored, but the " " in "\n foo''" is.) */ + bool atStartOfLine = true; /* = seen only whitespace in the current line */ + size_t minIndent = 1000000; + size_t curIndent = 0; + for (auto & [i_pos, i] : es) { + auto * str = std::get_if<StringToken>(&i); + if (!str || !str->hasIndentation) { + /* Anti-quotations and escaped characters end the current start-of-line whitespace. */ + if (atStartOfLine) { + atStartOfLine = false; + if (curIndent < minIndent) minIndent = curIndent; + } + continue; + } + for (size_t j = 0; j < str->s.size(); ++j) { + if (atStartOfLine) { + if (str->s[j] == ' ') + curIndent++; + else if (str->s[j] == '\n') { + /* Empty line, doesn't influence minimum + indentation. */ + curIndent = 0; + } else { + atStartOfLine = false; + if (curIndent < minIndent) minIndent = curIndent; + } + } else if (str->s[j] == '\n') { + atStartOfLine = true; + curIndent = 0; + } + } + } + + /* Strip spaces from each line. */ + std::vector<std::pair<PosIdx, std::unique_ptr<Expr>>> es2; + atStartOfLine = true; + size_t curDropped = 0; + size_t n = es.size(); + auto i = es.begin(); + const auto trimExpr = [&] (std::unique_ptr<Expr> e) { + atStartOfLine = false; + curDropped = 0; + es2.emplace_back(i->first, std::move(e)); + }; + const auto trimString = [&] (const StringToken t) { + std::string s2; + for (size_t j = 0; j < t.s.size(); ++j) { + if (atStartOfLine) { + if (t.s[j] == ' ') { + if (curDropped++ >= minIndent) + s2 += t.s[j]; + } + else if (t.s[j] == '\n') { + curDropped = 0; + s2 += t.s[j]; + } else { + atStartOfLine = false; + curDropped = 0; + s2 += t.s[j]; + } + } else { + s2 += t.s[j]; + if (t.s[j] == '\n') atStartOfLine = true; + } + } + + /* Remove the last line if it is empty and consists only of + spaces. */ + if (n == 1) { + std::string::size_type p = s2.find_last_of('\n'); + if (p != std::string::npos && s2.find_first_not_of(' ', p + 1) == std::string::npos) + s2 = std::string(s2, 0, p + 1); + } + + es2.emplace_back(i->first, std::make_unique<ExprString>(std::move(s2))); + }; + for (; i != es.end(); ++i, --n) { + std::visit(overloaded { trimExpr, trimString }, std::move(i->second)); + } + + /* If this is a single string, then don't do a concatenation. */ + if (es2.size() == 1 && dynamic_cast<ExprString *>(es2[0].second.get())) { + return std::move(es2[0].second); + } + return std::make_unique<ExprConcatStrings>(pos, true, std::move(es2)); +} + +} |