diff options
Diffstat (limited to 'src/parser.cpp')
| -rw-r--r-- | src/parser.cpp | 136 |
1 files changed, 106 insertions, 30 deletions
diff --git a/src/parser.cpp b/src/parser.cpp index 4ae13d3..4cefb28 100644 --- a/src/parser.cpp +++ b/src/parser.cpp @@ -53,6 +53,7 @@ namespace States { StateStart start; StateControl control; StateASCII ascii; + StateEscape escape; StateFCommand fcommand; StateChangeDir changedir; StateCondCommand condcommand; @@ -139,7 +140,7 @@ Execute::macro(const gchar *macro, bool locals) GotoTable *parent_goto_table = Goto::table; GotoTable macro_goto_table(false); - QRegisterTable *parent_locals; + QRegisterTable *parent_locals = NULL; State *parent_state = States::current; gint parent_pc = macro_pc; @@ -160,7 +161,20 @@ Execute::macro(const gchar *macro, bool locals) } try { - step(macro, strlen(macro)); + try { + step(macro, strlen(macro)); + } catch (Return) { + /* + * Macro returned - handle like regular + * end of macro, even though some checks + * are unnecessary here. + * macro_pc will still point to the return PC. + * We are still in the "escape" state and must + * reset it here, so it is not confused + * with a trailing ^[ in macro. + */ + States::current = &States::start; + } /* * Subsequent errors must still be @@ -172,12 +186,22 @@ Execute::macro(const gchar *macro, bool locals) throw Error("Label \"%s\" not found", Goto::skip_label); - if (States::current != &States::start) + if (States::current == &States::escape) { + /* + * Due to the deferred nature of ^[, + * it is valid to end in the "escape" state. + * FIXME: This could be avoided by signalling + * the state the end of macro but State::refresh() + * cannot be used :-(. + */ + expressions.discard_args(); + } else if (States::current != &States::start) { /* * can only happen if we returned because * of macro end */ throw Error("Unterminated command"); + } /* * This handles the problem of Q-Registers @@ -190,7 +214,7 @@ Execute::macro(const gchar *macro, bool locals) if (locals) QRegisters::locals->clear(); } catch (Error &error) { - error.set_coord(macro, strlen(macro)); + error.set_coord(macro, macro_pc); throw; /* forward */ } } catch (...) { @@ -726,7 +750,7 @@ StateStart::custom(gchar chr) tecoBool rc; /* - * <CTRL/x> commands implemented in StateCtrlCmd + * <CTRL/x> commands implemented in StateControl */ if (IS_CTL(chr)) return States::control.get_next_state(CTL_ECHO(chr)); @@ -1801,6 +1825,7 @@ StateControl::StateControl() : State() transitions['I'] = &States::insert_indent; transitions['U'] = &States::ctlucommand; transitions['^'] = &States::ascii; + transitions['['] = &States::escape; } State * @@ -1841,31 +1866,6 @@ StateControl::custom(gchar chr) break; /* - * Alternatives: ^[, <CTRL/[>, <ESC> - */ - /*$ - * ^[ -- Discard all arguments - * $ - * - * Pops and discards all values from the stack that - * might otherwise be used as arguments to following - * commands. - * Therefore it stops popping on stack boundaries like - * they are introduced by arithmetic brackets or loops. - * - * Note that ^[ is usually typed using the Escape key. - * CTRL+[ however is possible as well and equivalent to - * Escape in every manner. - * The Caret-[ notation however is processed like any - * ordinary command and only works as the discard-arguments - * command. - */ - case '[': - BEGIN_EXEC(&States::start); - expressions.discard_args(); - break; - - /* * Additional numeric operations */ /*$ @@ -1930,6 +1930,82 @@ StateASCII::custom(gchar chr) return &States::start; } +/* + * The Escape state is special, as it implements + * a kind of "lookahead" for the ^[ command (dicard all + * arguments). + * It is not executed immediately as usual in SciTECO + * but only if not followed by an escape character. + * This is necessary since $$ is the macro return + * and command-line termination command and it must not + * discard arguments. + * Deferred execution of ^[ is possible since it does + * not have any visible side-effects - its effects can + * only be seen when executing the following command. + */ +StateEscape::StateEscape() +{ + transitions['\0'] = this; +} + +State * +StateEscape::custom(gchar chr) +{ + /*$ + * [a1,a2,...]$$ -- Terminate command line or return from macro + * [a1,a2,...]^[$ + * + * Returns from the current macro invocation. + * The numeric stack is not modified, giving the + * effect of returning the arguments or stack contents + * preceding the command to the macro caller. + * It is generally semantically equivalent to reaching + * the end of the current macro but is executed faster. + * + * Therefore returning from the top-level macro in batch mode + * will exit the program or start up interactive mode depending + * on whether program exit has been requested. + * \(lqEX\fB$$\fP\(rq is thus a common idiom to exit + * prematurely. + * + * In interactive mode, returning from the top-level macro + * (i.e. typing \fB$$\fP at the command line) has the + * effect of command line termination. + * + * Only the first \fIescape\fP of \fB$$\fP may be typed + * in up-arrow mode as \fB^[$\fP \(em the second character + * must be a real escape character. + */ + if (chr == CTL_KEY_ESC) { + BEGIN_EXEC(&States::start); + throw Return(); + } + + /* + * Alternatives: ^[, <CTRL/[>, <ESC> + */ + /*$ + * ^[ -- Discard all arguments + * $ + * + * Pops and discards all values from the stack that + * might otherwise be used as arguments to following + * commands. + * Therefore it stops popping on stack boundaries like + * they are introduced by arithmetic brackets or loops. + * + * Note that ^[ is usually typed using the Escape key. + * CTRL+[ however is possible as well and equivalent to + * Escape in every manner. + * The Caret-[ notation however is processed like any + * ordinary command and only works as the discard-arguments + * command. + */ + if (mode == MODE_NORMAL) + expressions.discard_args(); + return States::start.get_next_state(chr); +} + StateECommand::StateECommand() : State() { transitions['\0'] = this; |