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#pragma once
///@file
#include "eval.hh"
namespace nix {
/**
* @note Storing a C-style `char *` and `size_t` allows us to avoid
* having to define the special members that using string_view here
* would implicitly delete.
*/
struct StringToken
{
const char * p;
size_t l;
bool hasIndentation;
operator std::string_view() const { return {p, l}; }
};
struct ParserLocation
{
int first_line, first_column;
int last_line, last_column;
// backup to recover from yyless(0)
int stashed_first_line, stashed_first_column;
int stashed_last_line, stashed_last_column;
void stash() {
stashed_first_line = first_line;
stashed_first_column = first_column;
stashed_last_line = last_line;
stashed_last_column = last_column;
}
void unstash() {
first_line = stashed_first_line;
first_column = stashed_first_column;
last_line = stashed_last_line;
last_column = stashed_last_column;
}
};
struct ParserState
{
SymbolTable & symbols;
PosTable & positions;
Expr * result;
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, Expr * e, const PosIdx pos);
Formals * validateFormals(Formals * formals, PosIdx pos = noPos, Symbol arg = {});
Expr * stripIndentation(const PosIdx pos,
std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>> && es);
PosIdx at(const ParserLocation & loc);
};
inline void ParserState::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 ParserState::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 ParserState::addAttr(ExprAttrs * attrs, AttrPath && attrPath, 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);
if (!attrs2) dupAttr(attrPath, pos, j->second.pos);
attrs = attrs2;
} else
dupAttr(attrPath, pos, j->second.pos);
} else {
ExprAttrs * nested = new ExprAttrs;
attrs->attrs[i->symbol] = ExprAttrs::AttrDef(nested, pos);
attrs = nested;
}
} else {
ExprAttrs *nested = new ExprAttrs;
attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, nested, pos));
attrs = nested;
}
}
// 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);
auto jAttrs = dynamic_cast<ExprAttrs *>(j->second.e);
if (jAttrs && ae) {
if (ae->inheritFromExprs && !jAttrs->inheritFromExprs)
jAttrs->inheritFromExprs = std::make_unique<std::vector<Expr *>>();
for (auto & ad : ae->attrs) {
auto j2 = jAttrs->attrs.find(ad.first);
if (j2 != jAttrs->attrs.end()) // Attr already defined in iAttrs, error.
dupAttr(ad.first, j2->second.pos, ad.second.pos);
jAttrs->attrs.emplace(ad.first, ad.second);
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->dynamicAttrs.insert(jAttrs->dynamicAttrs.end(), ae->dynamicAttrs.begin(), ae->dynamicAttrs.end());
if (ae->inheritFromExprs) {
jAttrs->inheritFromExprs->insert(jAttrs->inheritFromExprs->end(),
ae->inheritFromExprs->begin(), ae->inheritFromExprs->end());
}
} else {
dupAttr(attrPath, pos, j->second.pos);
}
} else {
// This attr path is not defined. Let's create it.
attrs->attrs.emplace(i->symbol, ExprAttrs::AttrDef(e, pos));
e->setName(i->symbol);
}
} else {
attrs->dynamicAttrs.push_back(ExprAttrs::DynamicAttrDef(i->expr, e, pos));
}
}
inline Formals * ParserState::validateFormals(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 Expr * ParserState::stripIndentation(const PosIdx pos,
std::vector<std::pair<PosIdx, std::variant<Expr *, StringToken>>> && es)
{
if (es.empty()) return new 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->l; ++j) {
if (atStartOfLine) {
if (str->p[j] == ' ')
curIndent++;
else if (str->p[j] == '\n') {
/* Empty line, doesn't influence minimum
indentation. */
curIndent = 0;
} else {
atStartOfLine = false;
if (curIndent < minIndent) minIndent = curIndent;
}
} else if (str->p[j] == '\n') {
atStartOfLine = true;
curIndent = 0;
}
}
}
/* Strip spaces from each line. */
auto * es2 = new std::vector<std::pair<PosIdx, Expr *>>;
atStartOfLine = true;
size_t curDropped = 0;
size_t n = es.size();
auto i = es.begin();
const auto trimExpr = [&] (Expr * e) {
atStartOfLine = false;
curDropped = 0;
es2->emplace_back(i->first, e);
};
const auto trimString = [&] (const StringToken & t) {
std::string s2;
for (size_t j = 0; j < t.l; ++j) {
if (atStartOfLine) {
if (t.p[j] == ' ') {
if (curDropped++ >= minIndent)
s2 += t.p[j];
}
else if (t.p[j] == '\n') {
curDropped = 0;
s2 += t.p[j];
} else {
atStartOfLine = false;
curDropped = 0;
s2 += t.p[j];
}
} else {
s2 += t.p[j];
if (t.p[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, new ExprString(std::move(s2)));
};
for (; i != es.end(); ++i, --n) {
std::visit(overloaded { trimExpr, trimString }, i->second);
}
/* If this is a single string, then don't do a concatenation. */
if (es2->size() == 1 && dynamic_cast<ExprString *>((*es2)[0].second)) {
auto *const result = (*es2)[0].second;
delete es2;
return result;
}
return new ExprConcatStrings(pos, true, es2);
}
inline PosIdx ParserState::at(const ParserLocation & loc)
{
return positions.add(origin, loc.first_line, loc.first_column);
}
}
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