diff --git a/src/libcmd/repl.cc b/src/libcmd/repl.cc index 57848a5d3..80c08bf1c 100644 --- a/src/libcmd/repl.cc +++ b/src/libcmd/repl.cc @@ -40,6 +40,7 @@ extern "C" { #include "markdown.hh" #include "local-fs-store.hh" #include "progress-bar.hh" +#include "print.hh" #if HAVE_BOEHMGC #define GC_INCLUDE_NEW @@ -425,6 +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; @@ -894,17 +896,6 @@ std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int m } -std::ostream & printStringValue(std::ostream & str, const char * string) { - str << "\""; - for (const char * i = string; *i; i++) - if (*i == '\"' || *i == '\\') str << "\\" << *i; - else if (*i == '\n') str << "\\n"; - else if (*i == '\r') str << "\\r"; - else if (*i == '\t') str << "\\t"; - else str << *i; - str << "\""; - return str; -} // FIXME: lot of cut&paste from Nix's eval.cc. @@ -922,12 +913,14 @@ std::ostream & NixRepl::printValue(std::ostream & str, Value & v, unsigned int m break; case nBool: - str << ANSI_CYAN << (v.boolean ? "true" : "false") << ANSI_NORMAL; + str << ANSI_CYAN; + printLiteralBool(str, v.boolean); + str << ANSI_NORMAL; break; case nString: str << ANSI_WARNING; - printStringValue(str, v.string.s); + printLiteralString(str, v.string.s); str << ANSI_NORMAL; break; @@ -964,10 +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 - printStringValue(str, i.first.c_str()); + printAttributeName(str, i.first); str << " = "; if (seen.count(i.second)) str << "«repeated»"; diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc index 18cfd9531..6668add8c 100644 --- a/src/libexpr/eval.cc +++ b/src/libexpr/eval.cc @@ -9,6 +9,7 @@ #include "filetransfer.hh" #include "function-trace.hh" #include "profiles.hh" +#include "print.hh" #include #include @@ -104,18 +105,10 @@ void Value::print(const SymbolTable & symbols, std::ostream & str, str << integer; break; case tBool: - str << (boolean ? "true" : "false"); + printLiteralBool(str, boolean); break; case tString: - str << "\""; - for (const char * i = string.s; *i; i++) - if (*i == '\"' || *i == '\\') str << "\\" << *i; - else if (*i == '\n') str << "\\n"; - else if (*i == '\r') str << "\\r"; - else if (*i == '\t') str << "\\t"; - else if (*i == '$' && *(i+1) == '{') str << "\\" << *i; - else str << *i; - str << "\""; + printLiteralString(str, string.s); break; case tPath: str << path; // !!! escaping? diff --git a/src/libexpr/nixexpr.cc b/src/libexpr/nixexpr.cc index eb6f062b4..1557cbbeb 100644 --- a/src/libexpr/nixexpr.cc +++ b/src/libexpr/nixexpr.cc @@ -3,6 +3,7 @@ #include "eval.hh" #include "symbol-table.hh" #include "util.hh" +#include "print.hh" #include @@ -60,45 +61,12 @@ Pos::operator std::shared_ptr() const return pos; } -/* Displaying abstract syntax trees. */ - -static void showString(std::ostream & str, std::string_view s) -{ - str << '"'; - for (auto c : s) - if (c == '"' || c == '\\' || c == '$') str << "\\" << c; - else if (c == '\n') str << "\\n"; - else if (c == '\r') str << "\\r"; - else if (c == '\t') str << "\\t"; - else str << c; - str << '"'; -} - +// 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 == '_')) { - showString(str, s); - return str; - } - for (auto c : s) - if (!((c >= 'a' && c <= 'z') || - (c >= 'A' && c <= 'Z') || - (c >= '0' && c <= '9') || - c == '_' || c == '\'' || c == '-')) { - showString(str, s); - return str; - } - str << s; - } - return str; + return printIdentifier(str, s); } void Expr::show(const SymbolTable & symbols, std::ostream & str) const @@ -118,7 +86,7 @@ void ExprFloat::show(const SymbolTable & symbols, std::ostream & str) const void ExprString::show(const SymbolTable & symbols, std::ostream & str) const { - showString(str, s); + printLiteralString(str, s); } void ExprPath::show(const SymbolTable & symbols, std::ostream & str) const diff --git a/src/libexpr/print.cc b/src/libexpr/print.cc new file mode 100644 index 000000000..d08672cfc --- /dev/null +++ b/src/libexpr/print.cc @@ -0,0 +1,78 @@ +#include "print.hh" + +namespace nix { + +std::ostream & +printLiteralString(std::ostream & str, const std::string_view string) +{ + str << "\""; + for (auto i = string.begin(); i != string.end(); ++i) { + if (*i == '\"' || *i == '\\') str << "\\" << *i; + else if (*i == '\n') str << "\\n"; + else if (*i == '\r') str << "\\r"; + else if (*i == '\t') str << "\\t"; + else if (*i == '$' && *(i+1) == '{') str << "\\" << *i; + else str << *i; + } + str << "\""; + return str; +} + +std::ostream & +printLiteralBool(std::ostream & str, bool boolean) +{ + str << (boolean ? "true" : "false"); + 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 new file mode 100644 index 000000000..f9cfc3964 --- /dev/null +++ b/src/libexpr/print.hh @@ -0,0 +1,48 @@ +#pragma once +/** + * @file + * @brief Common printing functions for the Nix language + * + * While most types come with their own methods for printing, they share some + * functions that are placed here. + */ + +#include + +namespace nix { + /** + * Print a string as a Nix string literal. + * + * Quotes and fairly minimal escaping are added. + * + * @param s The logical string + */ + std::ostream & printLiteralString(std::ostream & o, std::string_view s); + inline std::ostream & printLiteralString(std::ostream & o, const char * s) { + return printLiteralString(o, std::string_view(s)); + } + inline std::ostream & printLiteralString(std::ostream & o, const std::string & s) { + return printLiteralString(o, std::string_view(s)); + } + + /** 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); +} diff --git a/src/libstore/derivations.cc b/src/libstore/derivations.cc index abdfb1978..7eb5cd275 100644 --- a/src/libstore/derivations.cc +++ b/src/libstore/derivations.cc @@ -313,6 +313,15 @@ Derivation parseDerivation(const Store & store, std::string && s, std::string_vi } +/** + * Print a derivation string literal to an `std::string`. + * + * This syntax does not generalize to the expression language, which needs to + * escape `$`. + * + * @param res Where to print to + * @param s Which logical string to print + */ static void printString(std::string & res, std::string_view s) { boost::container::small_vector buffer; diff --git a/tests/repl.sh b/tests/repl.sh index be8adb742..2b3789521 100644 --- a/tests/repl.sh +++ b/tests/repl.sh @@ -79,6 +79,14 @@ testReplResponse ' "result: ${a}" ' "result: 2" +# check dollar escaping https://github.com/NixOS/nix/issues/4909 +# note the escaped \, +# \\ +# because the second argument is a regex +testReplResponse ' +"$" + "{hi}" +' '"\\${hi}"' + testReplResponse ' drvPath ' '".*-simple.drv"' \