init initNixExprHelpers

Pos | string int int | Pos |
NoPos | | Pos |

Function | Pattern Expr Pos | Expr |
Assert | Expr Expr Pos | Expr |
With | Expr Expr Pos | Expr |
If | Expr Expr Expr | Expr |
OpNot | Expr | Expr |
OpEq | Expr Expr | Expr |
OpNEq | Expr Expr | Expr |
OpAnd | Expr Expr | Expr |
OpOr | Expr Expr | Expr |
OpImpl | Expr Expr | Expr |
OpUpdate | Expr Expr | Expr |
SubPath | Expr Expr | Expr |
OpHasAttr | Expr string | Expr |
OpPlus | Expr Expr | Expr |
OpConcat | Expr Expr | Expr |
ConcatStrings | ATermList | Expr |
Call | Expr Expr | Expr |
Select | Expr string | Expr |
Var | string | Expr |
Int | int | Expr |

# Strings in the evaluator carry a so-called `context' (the ATermList)
# which is a list of strings representing store paths.  This is to
# allow users to write things like
#
#   "--with-freetype2-library=" + freetype + "/lib"
#
# where `freetype' is a derivation (or a source to be copied to the
# store).  If we just concatenated the strings without keeping track
# of the referenced store paths, then if the string is used as a
# derivation attribute, the derivation will not have the correct
# dependencies in its inputDrvs and inputSrcs.
#
# The semantics of the context is as follows: when a string with
# context C is used as a derivation attribute, then the derivations in
# C will be added to the inputDrvs of the derivation, and the other
# store paths in C will be added to the inputSrcs of the derivations.
#
# For canonicity, the store paths should be in sorted order.
Str | string ATermList | Expr |
Str | string | Expr | ObsoleteStr

# Internal to the parser, doesn't occur in ASTs.
IndStr | string | Expr |

# A path is a reference to a file system object that is to be copied
# to the Nix store when used as a derivation attribute.  When it is
# concatenated to a string (i.e., `str + path'), it is also copied and
# the resulting store path is concatenated to the string (with the
# store path in the context).  If a string or path is concatenated to
# a path (i.e., `path + str' or `path + path'), the result is a new
# path (if the right-hand side is a string, the context must be
# empty).
Path | string | Expr |

List | ATermList | Expr |
BlackHole | | Expr |
Undefined | | Expr |
Removed | | Expr |
PrimOp | int ATermBlob ATermList | Expr |
Attrs | ATermList | Expr |
Closed | Expr | Expr |
Rec | ATermList ATermList | Expr |
Bool | ATermBool | Expr |
Null | | Expr |

Bind | string Expr Pos | ATerm |
BindAttrPath | ATermList Expr Pos | ATerm | # desugared during parsing
Bind | string Expr | ATerm | ObsoleteBind
Inherit | Expr ATermList Pos | ATerm |

Scope | | Expr |

VarPat | string | Pattern |
AttrsPat | ATermList ATermBool | Pattern | # bool = `...'
AtPat | Pattern Pattern | Pattern |

Formal | string DefaultValue | ATerm |

DefaultValue | Expr | DefaultValue |
NoDefaultValue | | DefaultValue |

True | | ATermBool |
False | | ATermBool |

PrimOpDef | int ATermBlob | ATerm |

AttrRHS | Expr Pos | ATerm |

eTrue = makeBool(makeTrue())
eFalse = makeBool(makeFalse())
sOverrides = toATerm("__overrides")