Disclaimer: I work on Tree Notation. (https://github.com/treenotation/jtree https://github.com/treenotation/jtree) Here's a proposal: use a Tree Language. I c

Disclaimer: I work on Tree Notation. (https://github.com/treenotation/jtree https://github.com/treenotation/jtree) Here's a proposal: use a Tree Language. I created a demo for you called "Fished": https://github.com/breck7/fished https://github.com/breck7/fished. Took me just a few minutes but already get type check, autocomplete, syntax highlighting, and more. Tree Notation is early, and there will be kinks until the community is bigger, but I think it may be useful for you. http://treenotation.org/designer/#grammar%0A%20fishedNode%0A%20%20description%20A%20text%20serialization%20format%20for%20Fish%20Shell's%20history%20file.%0A%20%20root%0A%20%20inScope%20commandNode%0A%20anyCell%0A%20%20highlightScope%20string%0A%20intCell%0A%20%20highlightScope%20constant.numeric.integer%0A%20keywordCell%0A%20%20highlightScope%20keyword%0A%20abstractKeywordNode%0A%20%20firstCellType%20keywordCell%0A%20%20abstract%0A%20commandNode%0A%20%20extends%20abstractKeywordNode%0A%20%20inScope%20whenNode%20pwdNode%20pathsNode%0A%20%20cells%20anyCell%20anyCell%20anyCell%0A%20whenNode%0A%20%20extends%20abstractKeywordNode%0A%20%20cells%20intCell%0A%20pwdNode%0A%20%20extends%20abstractKeywordNode%0A%20%20cells%20anyCell%0A%20pathsNode%0A%20%20extends%20abstractKeywordNode%0A%20%20cells%20anyCell%0Asample%0A%20command%20git%20checkout%20file.txt%0A%20%20when%201565133286%0A%20%20pwd%20%2Fhome%2Fme%2Fdir%2F%0A%20%20paths%20file.txt http://treenotation.org/designer/#grammar%0A%20fishedNode%0A...