Object Pascal: full implementation. Test cleanup.

[jackhill/mal.git] / objpascal / step0_repl.pas

diff --git a/objpascal/step0_repl.pas b/objpascal/step0_repl.pas
new file mode 100644 (file)
index 0000000..6decb28
--- /dev/null
+++ b/objpascal/step0_repl.pas
@@ -0,0 +1,47 @@
+program Mal;
+
+Uses CMem,
+     Readline in 'pas-readline/src/readline.pas',
+     History in 'pas-readline/src/history.pas';
+
+var
+    Repl_Env: string = '';
+    Line : PChar;
+
+// read
+function READ(const Str: string) : string;
+begin
+    READ := Str;
+end;
+
+// eval
+function EVAL(Ast: string; Env: string) : string;
+begin
+    EVAL := Ast;
+end;
+
+// print
+function PRINT(Exp: string) : string;
+begin
+    PRINT := Exp;
+end;
+
+// repl
+function REP(Str: string) : string;
+begin
+    REP := PRINT(EVAL(READ(Str), Repl_Env));
+end;
+
+begin
+    while True do
+    begin
+        Line := Readline.readline('user> ');
+        if Line = Nil then
+            Halt(0);
+        if Line[0] = #0 then
+            continue;
+        add_history(Line);
+
+        WriteLn(REP(Line));
+    end;
+end.