Methods and systems for developing software can perform both compilation operations and read-evaluate-print-loop (REPL) operations on source code. In one embodiment, an integrated development environment can include a source code editor and a compiler and can perform the following operations: receiving source code and performing REPL operations as the source code is received; receiving edits in the source code for which REPL operations have been performed and compiling, by the compiler, the edited source code; and storing results of execution of the edited source code for use in subsequent REPL operations.