From 371ce08ef692433928ba3e8b814ea35464131a7f Mon Sep 17 00:00:00 2001
From: Kelvin Sherlock <ksherlock@gmail.com>
Date: Thu, 4 Feb 2016 21:57:17 -0500
Subject: [PATCH] continuation prompt.

---
 lempar.cxx          |  2 ++
 mpw-shell.cpp       |  8 +++++---
 phase2-parser.lemon | 16 +++++++++++++++-
 phase2.h            |  5 +++++
 4 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/lempar.cxx b/lempar.cxx
index 1ddc3a8..f70e47d 100644
--- a/lempar.cxx
+++ b/lempar.cxx
@@ -335,6 +335,8 @@ class yypParser : public LEMON_SUPER {
     }
     #endif
 
+    const yyStackEntry *begin() const { return &yystack[0]; }
+    const yyStackEntry *end() const { return &yystack[yyidx > 0 ? yyidx + 1: 0]; }
 
   protected:
   private:
diff --git a/mpw-shell.cpp b/mpw-shell.cpp
index c6a8b0f..a311336 100644
--- a/mpw-shell.cpp
+++ b/mpw-shell.cpp
@@ -96,7 +96,7 @@ int read_fd(phase1 &p, int fd) {
 	return 0;
 }
 
-int interactive(phase1 &p) {
+int interactive(phase1 &p, phase2& p2) {
 
 	std::string history_file = root();
 	history_file += ".history";
@@ -104,7 +104,9 @@ int interactive(phase1 &p) {
 
 
 	for(;;) {
-		char *cp = readline("# ");
+		const char *prompt = "# ";
+		if (p2.continuation()) prompt = "> ";
+		char *cp = readline(prompt);
 		if (!cp) break;
 
 		std::string s(cp);
@@ -233,7 +235,7 @@ int main(int argc, char **argv) {
 	}
 
 	if (isatty(STDIN_FILENO))
-		interactive(p1);
+		interactive(p1, p2);
 	else 
 		read_fd(p1, STDIN_FILENO);
 	p2.finish();
diff --git a/phase2-parser.lemon b/phase2-parser.lemon
index 1dc1eba..ae3668a 100644
--- a/phase2-parser.lemon
+++ b/phase2-parser.lemon
@@ -9,7 +9,7 @@
 #include "phase2.h"
 #include "command.h"
 #define LEMON_SUPER phase2_parser
-
+#include "phase2-parser.h"
 }
 
 %code {
@@ -17,6 +17,20 @@
 std::unique_ptr<phase2_parser> phase2_parser::make() {
 	return std::make_unique<yypParser>();
 }
+
+bool phase2_parser::continuation() const {
+	yypParser *self = (yypParser *)this;
+
+	for (const auto &e : *self) {
+		if (e.major == BEGIN) return true;
+		if (e.major == LPAREN) return true;
+		if (e.major == IF) return true;
+		if (e.major == AMP_AMP) return true;
+		if (e.major == PIPE_PIPE) return true;
+	}
+	return false;
+}
+
 }
 
 %left PIPE_PIPE AMP_AMP.
diff --git a/phase2.h b/phase2.h
index e33f18e..4eb049d 100644
--- a/phase2.h
+++ b/phase2.h
@@ -22,6 +22,7 @@ public:
 	virtual void parse_accept() override final;
 	virtual void parse_failure() override final;
 
+	bool continuation() const;
 private:
 	friend class phase2;
 
@@ -65,6 +66,10 @@ public:
 		return *this;
 	}
 
+	bool continuation() const {
+		return parser ? parser->continuation() : false;
+	}
+	
 private:
 
 	void parse(int, std::string &&);