Editing Mesa (programming language) (section)

===Semantics===
Mesa was a [[strongly typed programming language]] with type-checking across module boundaries, but with enough flexibility in its type system that heap allocators could be written in Mesa.<ref name="geschke">{{cite journal |doi=10.1145/359763.359771 |first1=Charles |last1=Geschke |author-link=Charles Geschke |first2=James H. |last2=Morris |author-link2=James H. Morris |first3=Edwin H. |last3=Satterthwaite |date=August 1977 |title=Early Experience with Mesa |journal=Communications of the ACM |volume=20 |issue=8 |pages=540–552 |s2cid=15737342 |doi-access=free }}</ref>

Due to its strict separation between interface and implementation, Mesa allows true incremental compilation and encourages [[computer architecture|architecture]]- and [[platform (computing)|platform]]-independent programming.  They also simplified source-level [[debugger|debugging]], including remote debugging via the [[Ethernet]].

Mesa had rich [[exception handling]] facilities, with four types of exceptions.  It had support for thread synchronization via monitors. Mesa was the first language to implement monitor BROADCAST, a concept introduced by the Pilot operating system.<ref name="monit">{{cite journal |doi=10.1145/358818.358824 |url=http://research.microsoft.com/lampson/23-ProcessesInMesa/Abstract.html |title=Experience with Processes and Monitors in Mesa |first1=Butler W. |last1=Lampson |author-link=Butler W. Lampson |first2=David D. |last2=Redell  |journal=Communications of the ACM |volume=23 |issue=2 |pages=105–117 |date=February 1980 |citeseerx=10.1.1.142.5765 |s2cid=1594544 }}</ref>