8. A method comprising: creating a data structure of real symbols representing source code generated by a background compiler during interactive program development in a programming environment, wherein a module executing on a computer adds at least one inferred symbol to the data structure during the interactive program development, wherein the at least one inferred symbol is based on source code entered in a source code editor wherein the at least one inferred symbol is inferred from the source code based on usage in the source code of an undefined symbol; during the interactive program development, utilizing the at least one inferred symbol in a tool that is part of the source code editor, wherein the tool displays the inferred symbol for the user's use in developing source code; and during the interactive program development, converting the inferred symbol into a real symbol in the data structure based on receiving user input indicating to perform the conversion.
8. A method comprising: creating a data structure of real symbols representing source code generated by a background compiler during interactive program development in a programming environment, wherein a module executing on a computer adds at least one inferred symbol to the data structure during the interactive program development, wherein the at least one inferred symbol is based on source code entered in a source code editor wherein the at least one inferred symbol is inferred from the source code based on usage in the source code of an undefined symbol; during the interactive program development, utilizing the at least one inferred symbol in a tool that is part of the source code editor, wherein the tool displays the inferred symbol for the user's use in developing source code; and during the interactive program development, converting the inferred symbol into a real symbol in the data structure based on receiving user input indicating to perform the conversion. 9. The method of claim 8 , wherein the data structure is a syntax tree, a semantic tree or a symbol table.