github.com/zclconf/go-cty

• function/stdlib: The merge function will no longer panic if all given maps are empty. (#58)
• function/stdlib: The various set-manipulation functions, like setunion, will no longer panic if given an unknown set value. (#59)

• cty: New Value.HasWhollyKnownType method, for testing whether a value's type could potentially change if any unknown values it was constructed from were to become known. (#55)
• convert: Fix incorrect panic when converting a tuple with a dynamic-typed null member into a list or set, due to overly-liberal type unification. (#56)

• function/stdlib: The jsonencode function will now correctly accept a null as its argument, and produce the JSON representation "null" rather than returning an error. (#54)

• function/stdlib: Fix various panics related to sets with unknown element types in the set-manipulation functions. (#52)
• convert: Don't panic when asked to convert a tuple of objects to a list type constraint containing a nested cty.DynamicPseudoType. (#53)

• function/stdlib: The string functions that partition strings into individual characters (grapheme clusters) now use the appropriate segmentation rules from Unicode 12.0.0, while previous versions used Unicode 9.0.0.
• function/stdlib: New functions Replace and RegexReplace for matching and replacing sequences of characters in a given string with another given string. (#45)
• function/stdlib: The function Substr will now produce a zero-length string when given a length of zero. Previously it was incorrectly returning the remainder of the string after the given offset. (#48)
• function/stdlib: The Floor and Ceil functions will now return an infinity if given an infinity, rather than returning the maximum/minimum integer value. (#51)
• cty: Convenience methods for constructing path index steps from normal Go int and string values. (#50)

• convert: Fix incorrect conversion rules for maps of maps that were leading to panics. This will now succeed in some more cases that ought to have been valid, and produce a proper error if there is no valid outcome. (#47)
• function/stdlib: Fix an implementation error in the Contains function that was introduced in 1.3.0, so it will now produce a correct result rather than failing with a confusing error message. (#46)

• convert: There are now conversions from map types to object types, as long as the given map type's element type is convertible to all of the object type's attribute types. (#42)
• function/stdlib: HashiCorp has contributed a number of additional functions to the standard library that were originally implemented directly inside their Terraform codebase: (#37)
  • Element: take an element from a list or tuple by index, using modulo wrap-around.
  • CoalesceList: return the first non-empty list argument.
  • Compact: take a list of strings and return a new list of strings with all empty strings removed.
  • Contains: returns true if a given value appears as an element in a list, tuple, or set.
  • Distinct: filters duplicate elements from a list while retaining the order of remaining items.
  • ChunkList: turn a list into a list-of-lists where each top-level list is a "chunk" of a particular size of elements from the input.
  • Flatten: given a sequence that might contain other sequences, eliminate any intermediate sequences to produce a flat sequence.
  • Keys: return a list of keys from a map or object value in lexical order.
  • Values: return a list of values from a map in the same order as Keys.
  • Lookup: conditional lookup of an element from a map if it's present, or a fallback value if not. (This one differs from its Terraform equivalent in that the default value argument is required.)
  • Merge: given one or more maps or objects, merge them together into a single collection.
  • ReverseList: given a list, return a new list with the same items in the opposite order.
  • SetProduct: compute the cartesian product of one or more sets.
  • Slice: extract a consecutive sub-list from a list.
  • Zipmap: given a pair of lists of the same length, interpret the first as keys and the second as corresponding values to produce a map.
  • A factory MakeToFunc to build functions that each convert to a particular type constraint.
  • TimeAdd: add a duration to a timestamp to produce a new timestamp.
  • Ceil and Floor: round a fractional value to the nearest integer, away from or towards zero respectively.
  • Log: computes a logarithm in a given base.
  • Pow: implements exponentiation.
  • ParseInt: parses a string containing digits in a particular base to produce a whole number value.
  • Join: concatenates the elements of a list of strings with a given separator to produce a string.
  • Split: partitions a string by a given separator, returning a list of strings.
  • Sort: sorts a list of strings into lexical order.
  • Chomp: removes one or more newline characters from the end of a given string, producing a new string.
  • Indent: prepends a number of spaces to all lines except the first in a given string, producing a new string.
  • Title: converts a string to "title case".
  • TrimSpace: trims spaces from the start and end of a given string.
  • Trim: generalization of TrimSpace that allows user-specified trimming characters.
  • TrimPrefix: like Trim but only at the start of the string.
  • TrimSuffix: like Trim but only at the end of the string.

• cty: Fixed an infinite recursion bug when working with sets containing nested data structures. (#35)

• cty: Applications can now implement a general subset of the cty operations when creating a capsule type. For more information, see Capsule Type Operation Definitions.
• cty: Values now support a new mechanism called Value Marks which can be used to transit additional metadata through expressions by marking the input values and then observing which marks propagated to the result value. This could be used, for example, to detect whether a value was derived from a particular other value in case that is useful for giving extra feedback in an error message.

• cty: Fixed a panic situation when trying to round-trip cty.Number values through encoding/gob. (#32)
• convert: Invalid string conversions to bool that use incorrect case will now give more actionable feedback. (#29)
• function/stdlib: The formatlist function will no longer panic if given an unknown tuple as one of its arguments.

• New method Path.Equals for robustly comparing cty.Path values. Previously callers might've used reflect.DeepEqual or similar, but that is not correct when a path contains a cty.Number index because reflect.DeepEqual does not correctly represent equality for number values. (#25)

Initial stable release.