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authorBoris Kolpackov <boris@codesynthesis.com>2020-04-28 08:48:53 +0200
committerBoris Kolpackov <boris@codesynthesis.com>2020-05-27 15:47:28 +0200
commitb808c255b6a9ddba085bf5646e7d20ec344f2e2d (patch)
tree32730291f7e6de8ef0a227905520dd66fb4ec0f3 /libbuild2/build/script/lexer.cxx
parent3552356a87402727e663131994fa87f48b3cd4fb (diff)
Initial support for ad hoc recipes (still work in progress)
Diffstat (limited to 'libbuild2/build/script/lexer.cxx')
-rw-r--r--libbuild2/build/script/lexer.cxx270
1 files changed, 270 insertions, 0 deletions
diff --git a/libbuild2/build/script/lexer.cxx b/libbuild2/build/script/lexer.cxx
new file mode 100644
index 0000000..7b8bdd4
--- /dev/null
+++ b/libbuild2/build/script/lexer.cxx
@@ -0,0 +1,270 @@
+// file : libbuild2/build/script/lexer.cxx -*- C++ -*-
+// license : MIT; see accompanying LICENSE file
+
+#include <libbuild2/build/script/lexer.hxx>
+
+using namespace std;
+
+namespace build2
+{
+ namespace build
+ {
+ namespace script
+ {
+ using type = token_type;
+
+ build2::script::redirect_aliases lexer::redirect_aliases {
+ type (type::in_file),
+ type (type::in_doc),
+ type (type::in_str),
+ type (type::out_file_ovr),
+ type (type::out_file_app),
+ nullopt};
+
+ void lexer::
+ mode (build2::lexer_mode m,
+ char ps,
+ optional<const char*> esc,
+ uintptr_t data)
+ {
+ bool a (false); // attributes
+
+ const char* s1 (nullptr);
+ const char* s2 (nullptr);
+
+ bool s (true); // space
+ bool n (true); // newline
+ bool q (true); // quotes
+
+ if (!esc)
+ {
+ assert (!state_.empty ());
+ esc = state_.top ().escapes;
+ }
+
+ switch (m)
+ {
+ case lexer_mode::command_line:
+ {
+ s1 = "=!|&<> $(#\t\n";
+ s2 = "== ";
+ break;
+ }
+ case lexer_mode::first_token:
+ {
+ // First token on the script line. Like command_line but
+ // recognizes variable assignments as separators.
+ //
+ s1 = "=+!|&<> $(#\t\n";
+ s2 = " == ";
+ break;
+ }
+ case lexer_mode::second_token:
+ {
+ // Second token on the script line. Like command_line but
+ // recognizes leading variable assignments.
+ //
+ // Note that to recognize only leading assignments we shouldn't
+ // add them to the separator strings (so this is identical to
+ // command_line).
+ //
+ s1 = "=!|&<> $(#\t\n";
+ s2 = "== ";
+ break;
+ }
+ case lexer_mode::variable_line:
+ {
+ // Like value except we don't recognize '{'.
+ //
+ s1 = " $(#\t\n";
+ s2 = " ";
+ break;
+ }
+ default:
+ {
+ base_lexer::mode (m, ps, esc);
+ return;
+ }
+ }
+
+ assert (ps == '\0');
+ state_.push (state {m, data, nullopt, a, ps, s, n, q, *esc, s1, s2});
+ }
+
+ token lexer::
+ next ()
+ {
+ token r;
+
+ switch (state_.top ().mode)
+ {
+ case lexer_mode::command_line:
+ case lexer_mode::first_token:
+ case lexer_mode::second_token:
+ case lexer_mode::variable_line:
+ r = next_line ();
+ break;
+ default: return base_lexer::next ();
+ }
+
+ if (r.qtype != quote_type::unquoted)
+ ++quoted_;
+
+ return r;
+ }
+
+ token lexer::
+ next_line ()
+ {
+ bool sep (skip_spaces ().first);
+
+ xchar c (get ());
+ uint64_t ln (c.line), cn (c.column);
+
+ state st (state_.top ()); // Make copy (see first/second_token).
+ lexer_mode m (st.mode);
+
+ auto make_token = [&sep, ln, cn] (type t)
+ {
+ return token (t, sep, ln, cn, token_printer);
+ };
+
+ // Handle attributes (do it first to make sure the flag is cleared
+ // regardless of what we return).
+ //
+ if (st.attributes)
+ {
+ assert (m == lexer_mode::variable_line);
+
+ state_.top ().attributes = false;
+
+ if (c == '[')
+ return make_token (type::lsbrace);
+ }
+
+ if (eos (c))
+ return make_token (type::eos);
+
+ // Expire certain modes at the end of the token. Do it early in case
+ // we push any new mode (e.g., double quote).
+ //
+ if (m == lexer_mode::first_token || m == lexer_mode::second_token)
+ state_.pop ();
+
+ // NOTE: remember to update mode() if adding new special characters.
+
+ switch (c)
+ {
+ case '\n':
+ {
+ // Expire variable value mode at the end of the line.
+ //
+ if (m == lexer_mode::variable_line)
+ state_.pop ();
+
+ sep = true; // Treat newline as always separated.
+ return make_token (type::newline);
+ }
+
+ // Variable expansion, function call, and evaluation context.
+ //
+ case '$': return make_token (type::dollar);
+ case '(': return make_token (type::lparen);
+ }
+
+ // Command line operator/separators.
+ //
+ if (m == lexer_mode::command_line ||
+ m == lexer_mode::first_token ||
+ m == lexer_mode::second_token)
+ {
+ switch (c)
+ {
+ // Comparison (==, !=).
+ //
+ case '=':
+ case '!':
+ {
+ if (peek () == '=')
+ {
+ get ();
+ return make_token (c == '=' ? type::equal : type::not_equal);
+ }
+ }
+ }
+ }
+
+ // Command operators.
+ //
+ if (m == lexer_mode::command_line ||
+ m == lexer_mode::first_token ||
+ m == lexer_mode::second_token)
+ {
+ if (optional<token> t = next_cmd_op (c, sep))
+ return move (*t);
+ }
+
+ // Variable assignment (=, +=, =+).
+ //
+ if (m == lexer_mode::second_token)
+ {
+ switch (c)
+ {
+ case '=':
+ {
+ if (peek () == '+')
+ {
+ get ();
+ return make_token (type::prepend);
+ }
+ else
+ return make_token (type::assign);
+ }
+ case '+':
+ {
+ if (peek () == '=')
+ {
+ get ();
+ return make_token (type::append);
+ }
+ }
+ }
+ }
+
+ // Otherwise it is a word.
+ //
+ unget (c);
+ return word (st, sep);
+ }
+
+ token lexer::
+ word (state st, bool sep)
+ {
+ lexer_mode m (st.mode);
+
+ // Customized implementation that handles special variable names ($>,
+ // $<, $~).
+ //
+ // @@ TODO: $(<), $(>): feels like this will have to somehow be
+ // handled at the top-level lexer level. Maybe provide a
+ // string of one-char special variable names as state::data?
+ //
+ if (m != lexer_mode::variable)
+ return base_lexer::word (st, sep);
+
+ xchar c (peek ());
+
+ if (c != '>' && c != '<' && c != '~')
+ return base_lexer::word (st, sep);
+
+ get ();
+
+ state_.pop (); // Expire the variable mode.
+ return token (string (1, c),
+ sep,
+ quote_type::unquoted, false,
+ c.line, c.column);
+ }
+ }
+ }
+}