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-rw-r--r--libbuild2/lexer.cxx96
1 files changed, 73 insertions, 23 deletions
diff --git a/libbuild2/lexer.cxx b/libbuild2/lexer.cxx
index 9176422..d82c135 100644
--- a/libbuild2/lexer.cxx
+++ b/libbuild2/lexer.cxx
@@ -713,9 +713,9 @@ namespace build2
}
token lexer::
- word (state st, bool sep)
+ word (const state& rst, bool sep)
{
- lexer_mode m (st.mode);
+ lexer_mode m (rst.mode);
xchar c (peek ());
assert (!eos (c));
@@ -746,22 +746,66 @@ namespace build2
lexeme += c;
};
- for (; !eos (c); c = peek ())
+ const state* st (&rst);
+ for (bool first (true); !eos (c); first = false, c = peek ())
{
// First handle escape sequences.
//
if (c == '\\')
{
- // In the variable mode we treat the beginning of the escape sequence
- // as a separator (think \"$foo\").
+ // In the variable mode we treat immediate `\` as the escape sequence
+ // literal and any following as a separator (think \"$foo\").
//
if (m == lexer_mode::variable)
- break;
+ {
+ if (!first)
+ break;
+
+ get ();
+ c = get ();
+
+ if (eos (c))
+ fail (c) << "unterminated escape sequence";
+
+ // For now we only support all the simple C/C++ escape sequences
+ // plus \0 (which in C/C++ is an octal escape sequence).
+ //
+ // In the future we may decide to support more elaborate sequences
+ // such as \xNN, \uNNNN, etc.
+ //
+ // Note: we return it in the literal form instead of translating for
+ // easier printing.
+ //
+ switch (c)
+ {
+ case '\'':
+ case '"':
+ case '?':
+ case '\\':
+ case '0':
+ case 'a':
+ case 'b':
+ case 'f':
+ case 'n':
+ case 'r':
+ case 't':
+ case 'v': lexeme = c; break;
+ default:
+ fail (c) << "unknown escape sequence \\" << c;
+ }
+
+ state_.pop ();
+ return token (type::escape,
+ move (lexeme),
+ sep,
+ qtype, qcomp, qfirst,
+ ln, cn);
+ }
get ();
xchar p (peek ());
- const char* esc (st.escapes);
+ const char* esc (st->escapes);
if (esc == nullptr ||
(*esc != '\0' && !eos (p) && strchr (esc, p) != nullptr))
@@ -777,7 +821,7 @@ namespace build2
continue;
}
else
- unget (c); // Treat as a normal character.
+ unget (c); // Fall through to treat as a normal character.
}
bool done (false);
@@ -806,8 +850,8 @@ namespace build2
get ();
state_.pop ();
- st = state_.top ();
- m = st.mode;
+ st = &state_.top ();
+ m = st->mode;
continue;
}
}
@@ -816,19 +860,17 @@ namespace build2
//
else if (m == lexer_mode::variable)
{
- bool first (lexeme.empty ());
-
// Handle special variable names, if any.
//
- if (first &&
- st.data != 0 &&
- strchr (reinterpret_cast<const char*> (st.data), c) != nullptr)
+ if (first &&
+ st->data != 0 &&
+ strchr (reinterpret_cast<const char*> (st->data), c) != nullptr)
{
get ();
lexeme += c;
done = true;
}
- else if (c != '_' && !(first ? alpha (c) : alnum (c)))
+ else if (c != '_' && !(lexeme.empty () ? alpha (c) : alnum (c)))
{
if (c != '.')
done = true;
@@ -848,17 +890,17 @@ namespace build2
{
// First check if it's a pair separator.
//
- if (c == st.sep_pair)
+ if (c == st->sep_pair)
done = true;
else
{
// Then see if this character or character sequence is a separator.
//
- for (const char* p (strchr (st.sep_first, c));
+ for (const char* p (strchr (st->sep_first, c));
p != nullptr;
p = done ? nullptr : strchr (p + 1, c))
{
- char s (st.sep_second[p - st.sep_first]);
+ char s (st->sep_second[p - st->sep_first]);
// See if it has a second.
//
@@ -876,13 +918,19 @@ namespace build2
// Handle single and double quotes if enabled for this mode and unless
// they were considered separators.
//
- if (st.quotes && !done)
+ if (st->quotes && !done)
{
auto quoted_mode = [this] (lexer_mode m)
{
+ // In the double-quoted mode we only do effective escaping of the
+ // special `$("\` characters plus `)` for symmetry. Nothing can be
+ // escaped in single-quoted.
+ //
+ const char* esc (m == lexer_mode::double_quoted ? "$()\"\\" : "");
+
state_.push (state {
m, 0, nullopt, false, false, '\0', false, true, true,
- state_.top ().escapes, nullptr, nullptr});
+ esc, nullptr, nullptr});
};
switch (c)
@@ -933,8 +981,8 @@ namespace build2
quoted_mode (lexer_mode::double_quoted);
- st = state_.top ();
- m = st.mode;
+ st = &state_.top ();
+ m = st->mode;
switch (qtype)
{
@@ -1090,6 +1138,8 @@ namespace build2
}
case '\\':
{
+ // See if this is line continuation.
+ //
get ();
if (peek () == '\n')