first step crenshaw

1 files changed, 71 insertions, 0 deletions

diff --git a/crenshaw/main.pas b/crenshaw/main.pas
new file mode 100644
index 0000000..3adc53b
--- /dev/null
+++ b/crenshaw/main.pas
@@ -0,0 +1,71 @@
+program Main;
+
+const TAB = ^I;
+
+var Look : char;
+
+procedure Error(s : string);
+begin
+	WriteLn;
+	WriteLn(^G, 'Error: ', s, '.');
+end;
+
+procedure GetChar;
+begin
+	Read(Look);
+end;
+
+procedure Abort(s : string);
+begin
+	Error(s);
+	Halt;
+end;
+
+procedure Expected(s : string);
+begin
+	Abort(s + ' expected');
+end;
+
+procedure Match(c : char);
+begin
+	if c = Look then GetChar
+	else Expected('''' + c + '''');
+end;
+
+function IsAlpha(c : char) : boolean;
+begin
+	IsAlpha := upcase(c) in ['A'..'Z'];
+end;
+
+function IsDigit(c : char) : boolean;
+begin
+	IsDigit := c in ['0'..'9'];
+end;
+
+function GetName : char;
+begin
+	if not IsAlpha(Look) then Expected('Name');
+	GetName := UpCase(Look);
+	GetChar;
+end;
+
+function GetNum : char;
+begin
+	if not IsDigit(Look) then Expected('Integer');
+	GetNum := Look;
+	GetChar;
+end;
+
+procedure Emit(s : string);
+begin
+	Write(TAB, s);
+end;
+
+procedure EmitLn(s : string);
+begin
+	WriteLn;
+	Emit(s);
+end;
+
+begin
+end.