From 20b6ef15c03fb442eb6c96e1aaa301805be74c1e Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Wed, 24 May 2017 09:12:24 +0200
Subject: Add python rip interpreter 'rippy'

---
 rippy/rippy.py | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100755 rippy/rippy.py

diff --git a/rippy/rippy.py b/rippy/rippy.py
new file mode 100755
index 0000000..d6158bb
--- /dev/null
+++ b/rippy/rippy.py
@@ -0,0 +1,158 @@
+#!/usr/bin/env python3
+
+import sys
+
+rip_mode=False
+
+if len(sys.argv)!=2:
+    print("Usage: ./rippy.py <file.rip>",file=sys.stderr)
+    sys.exit(1)
+
+def error(msg):
+    if rip_mode:
+        msg="rip"
+    print(msg,file=sys.stderr)
+    sys.exit(1)
+
+def make_jumpmap(source):
+    jm={}
+    stk=[]
+    for i in range(len(source)):
+        if source[i]=="[":
+            stk.append(i)
+        elif source[i]=="]":
+            if len(stk)==0:
+                error("Too many ']' in source")
+            jm[stk[-1]]=i
+            jm[i]=stk[-1]
+            stk.pop()
+    if len(stk)!=0:
+        error("Too many '[' in source")
+    return jm
+
+def stack_check(stk,opname,nelems):
+    if len(stk)==0:
+        error(opname+" needs "+nelems+" element"+("s" if nelems!=1 else "")+" on the stack")
+
+def stack_pop(stk,opname,nelems):
+    stack_check(stk,opname,nelems)
+    e=stk[-1]
+    stk.pop()
+    return e
+
+
+def rip(source,jm):
+    ip=0
+    stk=[]
+    cstk=[]
+    lastif=None
+    while ip<len(source):
+        if source[ip] in " \t\n":
+            ip+=1
+            continue
+
+        if lastif!=None and source[ip]!="[":
+            error("'[' expected after '"+lastif+"'")
+
+        if source[ip] in "0123456789":
+            stk.append(int(source[ip]))
+        elif source[ip]=="P":
+            stack_pop(stk,"Pop",1)
+        elif source[ip]=="S":
+            stack_check(stk,"Swap",2)
+            stk[-2],stk[-1]=stk[-1],stk[-2]
+        elif source[ip]=="D":
+            stack_check(stk,"Duplicate",1)
+            stk.append(stk[-1])
+        elif source[ip]=="i":
+            stack_check(stk,"Increment",1)
+            stk[-1]+=1
+        elif source[ip]=="d":
+            stack_check(stk,"Decrement",1)
+            stk[-1]-=1
+        elif source[ip]=="r":
+            a=stack_pop(stk,"Roll",1)
+            if a<0:
+                error("Negative roll amount")
+            if a>1:
+                stack_check(stk,"Roll("+str(a)+")",a)
+                stk[-a],stk[-a+1:-1]=stk[-1],stk[-a:-2]
+        elif source[ip]=="R":
+            a=stack_pop(stk,"Reverse roll",1)
+            if a<0:
+                error("Negative reverse roll amount")
+            if a>1:
+                stack_check(stk,"Reverse roll("+str(a)+")",a)
+                stk[-a:-2],stk[-1]=stk[-a+1:-1],stk[-a]
+        elif source[ip]=="l":
+            stk.append(len(stk))
+        elif source[ip] in "asmqMpGLE":
+            names={
+                "a": "Add", "s": "Subtract", "m": "Multiply", "q": "Quotient",
+                "M": "Modulo", "p": "Power", "G": "Greater", "L": "Less", "E": "Equal"
+            }
+            funcs={
+                "a": lambda a,b: a+b, "s": lambda a,b: a-b, "m": lambda a,b: a*b,
+                "q": lambda a,b: a//b, "M": lambda a,b: a%b, "p": lambda a,b: a**b,
+                "G": lambda a,b: a>b, "L": lambda a,b: a<b, "E": lambda a,b: a==b,
+            }
+            b=stack_pop(stk,names[source[ip]],2)
+            a=stack_pop(stk,names[source[ip]],2)
+            stk.append(funcs[source[ip]](a,b))
+        elif source[ip]=="n":
+            stk.append(stack_pop(stk,"Not",1)!=0)
+        elif source[ip] in "IW":
+            if lastif!=None:
+                error("'"+source[lastif]+" without codeblock")
+            lastif=source[ip]
+        elif source[ip]=="[":
+            if lastif==None:
+                error("'[' without I or W")
+            if stack_pop(stk,"'[' for '"+lastif+"'",1)!=0:
+                cstk.append(lastif)
+            else:
+                ip=jm[ip]
+            lastif=None
+        elif source[ip]=="]":
+            if cstk[-1]=="W":
+                ip=jm[ip]-1
+                lastif=cstk[-1]
+            else:
+                cstk.pop()
+        elif source[ip]=="o":
+            n=stack_pop(stk,"Output character",1)
+            if n<0 or n>255:
+                error("Invalid output byte")
+            print(chr((n%256+256)%256),end="")
+        elif source[ip]=="O":
+            n=stack_pop(stk,"Output number",1)
+            print(n,end="")
+        elif source[ip]=="g":
+            c=sys.stdin.read(1)
+            if len(c)==0:
+                stk.append(-1)
+            else:
+                stk.append(ord(c))
+        elif source[ip]=="'":
+            if ip+1>=len(source):
+                error("Single-quote at end of file")
+            stk.append(ord(source[ip+1]))
+            ip+=1
+        else:
+            error("Unrecognised command '"+source[ip]+"'")
+
+        ip+=1
+
+
+def main():
+    sourcefname=sys.argv[1]
+    with open(sourcefname,"r") as f:
+        source=f.read()
+
+    jm=make_jumpmap(source)
+
+    rip(source,jm)
+
+
+if __name__=="__main__":
+    main()
-- 
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