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authorBoris Kolpackov <boris@codesynthesis.com>2020-05-01 17:09:59 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2020-05-01 17:12:04 +0200
commit630b498533f5a9a1e9d40893f4806ef855f1e03b (patch)
tree18657642a3d0deffc1ed14ad449bd6f3ac4b1e64 /libbuild2
parentc7e9f97fc7684c01c692916be1ac2cfc92024a0c (diff)
Fix outstanding issue with directive vs assignment differentiation
Specifically, now the following does the right thing: print +foo
Diffstat (limited to 'libbuild2')
-rw-r--r--libbuild2/lexer.cxx23
-rw-r--r--libbuild2/lexer.hxx15
-rw-r--r--libbuild2/parser.cxx20
3 files changed, 42 insertions, 16 deletions
diff --git a/libbuild2/lexer.cxx b/libbuild2/lexer.cxx
index 5ffac54..c0cadd3 100644
--- a/libbuild2/lexer.cxx
+++ b/libbuild2/lexer.cxx
@@ -11,12 +11,26 @@ namespace build2
{
using type = token_type;
- pair<char, bool> lexer::
- peek_char ()
+ pair<pair<char, char>, bool> lexer::
+ peek_chars ()
{
sep_ = skip_spaces ();
- xchar c (peek ());
- return make_pair (eos (c) ? '\0' : char (c), sep_);
+ char r[2] = {'\0', '\0'};
+
+ xchar c0 (peek ());
+ if (!eos (c0))
+ {
+ get (c0);
+ r[0] = c0;
+
+ xchar c1 (peek ());
+ if (!eos (c1))
+ r[1] = c1;
+
+ unget (c0);
+ }
+
+ return make_pair (make_pair (r[0], r[1]), sep_);
}
void lexer::
@@ -31,7 +45,6 @@ namespace build2
bool n (true); // newline
bool q (true); // quotes
-
if (!esc)
{
assert (!state_.empty ());
diff --git a/libbuild2/lexer.hxx b/libbuild2/lexer.hxx
index e9a3149..02112cb 100644
--- a/libbuild2/lexer.hxx
+++ b/libbuild2/lexer.hxx
@@ -142,12 +142,17 @@ namespace build2
virtual token
next ();
- // Peek at the first character of the next token. Return the character
- // or '\0' if the next token will be eos. Also return an indicator of
- // whether the next token will be separated.
+ // Peek at the first two characters of the next token(s). Return the
+ // characters or '\0' if either would be eos. Also return an indicator of
+ // whether the next token would be separated. Note: cannot be used to peek
+ // at the first character of a line.
//
- pair<char, bool>
- peek_char ();
+ // Note also that it assumes that the current mode and the potential new
+ // mode in which these characters will actually be parsed use the same
+ // whitespace separation (the sep_space and sep_newline values).
+ //
+ pair<pair<char, char>, bool>
+ peek_chars ();
protected:
struct state
diff --git a/libbuild2/parser.cxx b/libbuild2/parser.cxx
index 1432d4b..f0eac97 100644
--- a/libbuild2/parser.cxx
+++ b/libbuild2/parser.cxx
@@ -5747,7 +5747,7 @@ namespace build2
//
// - it is not quoted [so a keyword can always be escaped] and
// - next token is '\n' (or eos) or '(' [so if(...) will work] or
- // - next token is separated and is not '=', '=+', or '+=' [which
+ // - next token is separated and is not '=', '=+', '+=', or '?=' [which
// means a "directive trailer" can never start with one of them].
//
// See tests/keyword.
@@ -5757,15 +5757,23 @@ namespace build2
// We cannot peek at the whole token here since it might have to be
// lexed in a different mode. So peek at its first character.
//
- pair<char, bool> p (lexer_->peek_char ());
- char c (p.first);
+ pair<pair<char, char>, bool> p (lexer_->peek_chars ());
+ char c0 (p.first.first);
+ char c1 (p.first.second);
- // @@ Just checking for leading '+' is not sufficient, for example:
+ // Note that just checking for leading '+'/'?' is not sufficient, for
+ // example:
//
// print +foo
//
- return c == '\n' || c == '\0' || c == '(' ||
- (p.second && c != '=' && c != '+');
+ // So wepeek at one more character since what we expect next ('=') can't
+ // be whitespace-separated.
+ //
+ return c0 == '\n' || c0 == '\0' || c0 == '(' ||
+ (p.second &&
+ c0 != '=' &&
+ (c0 != '+' || c1 != '=') &&
+ (c0 != '?' || c1 != '='));
}
return false;