1 files changed, 85 insertions, 0 deletions
diff --git a/stp/parser/let-funcs.cpp b/stp/parser/let-funcs.cpp
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+/********************************************************************
+ * AUTHORS: Vijay Ganesh, David L. Dill
+ *
+ * BEGIN DATE: November, 2005
+ *
+ * LICENSE: Please view LICENSE file in the home dir of this Program
+ ********************************************************************/
+// -*- c++ -*-
+
+#include "../AST/AST.h"
+#include <stdlib.h>
+
+namespace BEEV {
+  //external parser table for declared symbols. Only symbols which are
+  //declared are stored here.
+  ASTNodeSet _parser_symbol_table;
+
+  // FUNC: This function maintains a map between LET-var names and
+  // LET-expressions
+  //
+  //1. if the Let-var is already defined in the LET scope, then the
+  //1. function returns an error.
+  //
+  //2. if the Let-var is already declared variable in the input, then
+  //2. the function returns an error
+  //
+  //3. otherwise add the <var,letExpr> pair to the _letid_expr table.
+  void BeevMgr::LetExprMgr(const ASTNode& var, const ASTNode& letExpr) {
+    ASTNodeMap::iterator it;
+    if(((it = _letid_expr_map.find(var)) != _letid_expr_map.end()) && 
+       it->second != ASTUndefined) {      
+      FatalError("LetExprMgr:The LET-var v has already been defined in this LET scope: v =", var);
+    }
+
+    if(_parser_symbol_table.find(var) != _parser_symbol_table.end()) {
+      FatalError("LetExprMgr:This var is already declared. cannot redeclare as a letvar: v =", var);
+    }
+
+    _letid_expr_map[var] = letExpr;   
+  }
+
+  //this function looksup the "var to letexpr map" and returns the
+  //corresponding letexpr. if there is no letexpr, then it simply
+  //returns the var.
+  ASTNode BeevMgr::ResolveID(const ASTNode& v) {
+    if(v.GetKind() != SYMBOL) {
+      return v;
+    }
+
+    if(_parser_symbol_table.find(v) != _parser_symbol_table.end()) {
+      return v;
+    }
+
+    ASTNodeMap::iterator it;
+    if((it =_letid_expr_map.find(v)) != _letid_expr_map.end()) {
+      if(it->second == ASTUndefined) 
+	FatalError("Unresolved Identifier: ",v);
+      else
+	return it->second;
+    }
+
+    //this is to mark the let-var as undefined. the let var is defined
+    //only after the LetExprMgr has completed its work, and until then
+    //'v' is undefined. 
+    //
+    //declared variables also get stored in this map, but there value
+    //is ASTUndefined. This is really a hack. I don't know how to get
+    //rid of this hack.
+    _letid_expr_map[v] = ASTUndefined;
+    return v;    
+  }
+  
+  // This function simply cleans up the LetID -> LetExpr Map.   
+  void BeevMgr::CleanupLetIDMap(void) { 
+    ASTNodeMap::iterator it = _letid_expr_map.begin();
+    ASTNodeMap::iterator itend = _letid_expr_map.end();
+    for(;it!=itend;it++) {
+      if(it->second != ASTUndefined) {
+	it->first.SetValueWidth(0);
+	it->first.SetIndexWidth(0);
+      }
+    }
+    _letid_expr_map.clear();
+  }
+};