The type for concrete syntax trees of POSIX shell scripts. These trees are produced by the Morbig parser.

These type definitions refer directly to the grammar production rules of the POSIX standard. We use the following convention to name data constructors: given a rule A -> P1 ... PN of the grammar, the constructor for this rule starts with the name of the non terminal A and continues with the names of producers Pi appearing in the right-hand-side of the production rule. We do not need types for operators and reserved words.

These concrete syntax trees are actually richer than the production trees defined by the grammar. Indeed, they also embed concrete syntax trees for WORDs while the grammar sees WORDs are mere tokens. For instance, echo `cat bar` is interpreted by the grammar as a simple command with two WORDs echo and `cat bar`. Morbig does not stop its work here: it also parses `cat bar` and the resulting concrete syntax tree is attached to the WORD `cat bar`. See the type definition for word below for more details.

The PPX syntax extension package "visitors", written by François Pottier, is used to macro-generate many traversal functions over this concrete syntax tree. Note that we expose the .ml file of this module because the types generated by visitors are too complex to be displayed.

The two IoHere constructors have two arguments. The second argument is the word holding the contents of the here document, which does not figure in the grammar.