From b6125772d7d5f82d48873fc93a7f261832154b14 Mon Sep 17 00:00:00 2001 From: Robert Hensing Date: Sun, 16 Apr 2023 14:07:35 +0200 Subject: [PATCH] libexpr: Move identifier-like printing to print.cc --- src/libcmd/repl.cc | 6 ++--- src/libexpr/nixexpr.cc | 27 +++-------------------- src/libexpr/print.cc | 50 ++++++++++++++++++++++++++++++++++++++++++ src/libexpr/print.hh | 18 +++++++++++++++ 4 files changed, 73 insertions(+), 28 deletions(-) diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc index 806dce024..80c08bf1c 100644 --- a/src/libcmd/repl.cc +++ b/src/libcmd/repl.cc @@ -426,6 +426,7 @@ StringSet NixRepl::completePrefix(const std::string & prefix) } +// FIXME: DRY and match or use the parser static bool isVarName(std::string_view s) { if (s.size() == 0) return false; @@ -956,10 +957,7 @@ std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int m sorted.emplace(state->symbols[i.name], i.value); for (auto & i : sorted) { - if (isVarName(i.first)) - str << i.first; - else - printLiteralString(str, i.first); + printAttributeName(str, i.first); str << " = "; if (seen.count(i.second)) str << "«repeated»"; diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc index d8f3cd701..1557cbbeb 100644 --- a/src/libexpr/nixexpr.cc +++ b/src/libexpr/nixexpr.cc @@ -61,33 +61,12 @@ Pos::operator std::shared_ptr() const return pos; } -/* Displaying abstract syntax trees. */ - +// FIXME: remove, because *symbols* are abstract and do not have a single +// textual representation; see printIdentifier() std::ostream & operator <<(std::ostream & str, const SymbolStr & symbol) { std::string_view s = symbol; - - if (s.empty()) - str << "\"\""; - else if (s == "if") // FIXME: handle other keywords - str << '"' << s << '"'; - else { - char c = s[0]; - if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_')) { - printLiteralString(str, s); - return str; - } - for (auto c : s) - if (!((c >= 'a' && c <= 'z') || - (c >= 'A' && c <= 'Z') || - (c >= '0' && c <= '9') || - c == '_' || c == '\'' || c == '-')) { - printLiteralString(str, s); - return str; - } - str << s; - } - return str; + return printIdentifier(str, s); } void Expr::show(const SymbolTable & symbols, std::ostream & str) const diff --git a/src/libexpr/print.cc b/src/libexpr/print.cc index 282903b72..d08672cfc 100644 --- a/src/libexpr/print.cc +++ b/src/libexpr/print.cc @@ -25,4 +25,54 @@ printLiteralBool(std::ostream & str, bool boolean) return str; } +std::ostream & +printIdentifier(std::ostream & str, std::string_view s) { + if (s.empty()) + str << "\"\""; + else if (s == "if") // FIXME: handle other keywords + str << '"' << s << '"'; + else { + char c = s[0]; + if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_')) { + printLiteralString(str, s); + return str; + } + for (auto c : s) + if (!((c >= 'a' && c <= 'z') || + (c >= 'A' && c <= 'Z') || + (c >= '0' && c <= '9') || + c == '_' || c == '\'' || c == '-')) { + printLiteralString(str, s); + return str; + } + str << s; + } + return str; +} + +// FIXME: keywords +static bool isVarName(std::string_view s) +{ + if (s.size() == 0) return false; + char c = s[0]; + if ((c >= '0' && c <= '9') || c == '-' || c == '\'') return false; + for (auto & i : s) + if (!((i >= 'a' && i <= 'z') || + (i >= 'A' && i <= 'Z') || + (i >= '0' && i <= '9') || + i == '_' || i == '-' || i == '\'')) + return false; + return true; +} + +std::ostream & +printAttributeName(std::ostream & str, std::string_view name) { + if (isVarName(name)) + str << name; + else + printLiteralString(str, name); + return str; +} + + } diff --git a/src/libexpr/print.hh b/src/libexpr/print.hh index 98dd2008d..f9cfc3964 100644 --- a/src/libexpr/print.hh +++ b/src/libexpr/print.hh @@ -27,4 +27,22 @@ namespace nix { /** Print `true` or `false`. */ std::ostream & printLiteralBool(std::ostream & o, bool b); + + /** + * Print a string as an attribute name in the Nix expression language syntax. + * + * Prints a quoted string if necessary. + */ + std::ostream & printAttributeName(std::ostream & o, std::string_view s); + + /** + * Print a string as an identifier in the Nix expression language syntax. + * + * FIXME: "identifier" is ambiguous. Identifiers do not have a single + * textual representation. They can be used in variable references, + * let bindings, left-hand sides or attribute names in a select + * expression, or something else entirely, like JSON. Use one of the + * `print*` functions instead. + */ + std::ostream & printIdentifier(std::ostream & o, std::string_view s); }