1 files changed, 116 insertions, 0 deletions
diff --git a/appl/alphabet/main/pretty.b b/appl/alphabet/main/pretty.b
new file mode 100644
index 00000000..52d8b32f
--- /dev/null
+++ b/appl/alphabet/main/pretty.b
@@ -0,0 +1,116 @@
+implement Pretty, Mainmodule;
+include "sys.m";
+	sys: Sys;
+include "draw.m";
+include "sh.m";
+	sh: Sh;
+	n_BLOCK,  n_VAR, n_BQ, n_BQ2, n_REDIR,
+	n_DUP, n_LIST, n_SEQ, n_CONCAT, n_PIPE, n_ADJ,
+	n_WORD, n_NOWAIT, n_SQUASH, n_COUNT,
+	n_ASSIGN, n_LOCAL,
+	GLOB: import Sh;
+include "alphabet/reports.m";
+	reports: Reports;
+		Report, report: import reports;
+include "alphabet.m";
+	alphabet: Alphabet;
+		Value: import alphabet;
+
+Pretty: module {};
+
+typesig(): string
+{
+	return "sc";
+}
+
+init()
+{
+	sys = load Sys Sys->PATH;
+	alphabet = load Alphabet Alphabet->PATH;
+	sh = load Sh Sh->PATH;
+	sh->initialise();
+}
+
+quit()
+{
+}
+
+run(nil: ref Draw->Context, nil: ref Reports->Report, nil: chan of string,
+		nil: list of (int, list of ref Value),
+		args: list of ref Value): ref Value
+{
+	{
+		return ref Value.Vs(pretty((hd args).c().i, 0));
+	}exception{
+	"bad expr" =>
+		return nil;
+	}
+}
+
+pretty(n: ref Sh->Cmd, depth: int): string
+{
+	if (n == nil)
+		return nil;
+	s: string;
+	case n.ntype {
+	n_BLOCK =>
+		s = "{\n"+tabs(depth+1)+pretty(n.left,depth+1) + "\n"+tabs(depth)+"}";
+	n_VAR =>
+		s = "$" + pretty(n.left, depth);
+	n_LIST =>
+		s = "(" + pretty(n.left, depth) + ")";
+	n_SEQ =>
+		s = pretty(n.left, depth) + "\n"+tabs(depth)+pretty(n.right, depth);
+	n_PIPE =>
+		s = pretty(n.left, depth) + " |\n"+tabs(depth)+pretty(n.right, depth);
+	n_ADJ =>
+		s = pretty(n.left, depth) + " " + pretty(n.right, depth);
+	n_WORD =>
+		s = quote(n.word, 1);
+	n_BQ2 =>
+		# if we can't do it, revert to ugliness.
+		{
+			s = "\"" + pretty(n.left, depth);
+		} exception {
+		"bad expr" =>
+			s = sh->cmd2string(n);
+		}
+	* =>
+		raise "bad expr";
+	}
+	return s;
+}
+
+tabs(n: int): string
+{
+	s: string;
+	while(n-- > 0)
+		s[len s] = '\t';
+	return s;
+}
+
+# stolen from sh.y
+quote(s: string, glob: int): string
+{
+	needquote := 0;
+	t := "";
+	for (i := 0; i < len s; i++) {
+		case s[i] {
+		'{' or '}' or '(' or ')' or '`' or '&' or ';' or '=' or '>' or '<' or '#' or
+		'|' or '*' or '[' or '?' or '$' or '^' or ' ' or '\t' or '\n' or '\r' =>
+			needquote = 1;
+		'\'' =>
+			t[len t] = '\'';
+			needquote = 1;
+		GLOB =>
+			if (glob) {
+				if (i < len s - 1)
+					i++;
+			}
+		}
+		t[len t] = s[i];
+	}
+	if (needquote || t == nil)
+		t = "'" + t + "'";
+	return t;
+}