UMHDL
Integrated Development Environment (IDE) for learning HDL
...It is an open-source application created at the Miguel Hernández University (UMH). The aim for the UMHDL development was to have a graphical application that allows learning the VHDL language without licensing restrictions (using some existing open-source tools) and requiring few resources. So, the interface developed acts as a front-end that allows writing code (with syntax highlighting), invokes an external VHDL compiler and simulator (such as GHDL), and displays the result of the simulation graphically as waveforms (invoking to GTKWave).