Improve post! and DID result interface and add GroupContrasts (#33)

Author: junyuan-chen

src/DiffinDiffsBase.jl

@@ -14,7 +14,7 @@ using PooledArrays: _label
 using PrettyTables: pretty_table
 using Reexport
 using StatsBase: CoefTable, Weights, stderror, uweights
-using StatsFuns: tdistccdf, tdistinvcdf
+using StatsFuns: normccdf, norminvcdf, tdistccdf, tdistinvcdf
 @reexport using StatsModels
 using StatsModels: Schema
 using StructArrays: StructArray
@@ -111,6 +111,7 @@ export cb,
        CheckData,
        GroupTreatintterms,
        GroupXterms,
+       GroupContrasts,
        CheckVars,
        GroupSample,
        MakeWeights,
@@ -124,6 +125,7 @@ export cb,
        DIDResult,
        AggregatedDIDResult,
        vce,
+       treatment,
        outcomename,
        treatnames,
        treatcells,

src/StatsProcedures.jl

@@ -604,11 +604,13 @@ end
     @specset [option option=val ...] default_args... for v in (...) ... end
     @specset [option option=val ...] default_args... for v in (...), w in (...) ... end
 
-Construct a vector of [`StatsSpec`](@ref) with shared default values for arguments
+Construct a vector of [`StatsSpec`](@ref)s with shared default values for arguments
 and then conduct the procedures by calling [`proceed`](@ref).
+The vector of [`StatsSpec`](@ref)s and a vector of result objects are returned,
+unless alternative behavior is specified with the `option`s.
 
 # Arguments
-- `[option option=val ...]`: optional settings for @specset including keyword arguments for [`proceed`](@ref).
+- `[option option=val ...]`: optional settings for `@specset` including keyword arguments for [`proceed`](@ref).
 - `default_args...`: optional default values for arguments shared by all [`StatsSpec`](@ref)s.
 - `code block`: a `begin/end` block or a `for` loop containing arguments for constructing [`StatsSpec`](@ref)s.
 
@@ -634,7 +636,7 @@ For options that take a Boolean value,
 specifying the name of the option is enough for setting the value to be true.
     
 The following options are available for altering the behavior of `@specset`:
-- `noproceed::Bool=false`: do not call [`proceed`](@ref) and return the vector of [`StatsSpec`](@ref).
+- `noproceed::Bool=false`: do not call [`proceed`](@ref) and only return the vector of [`StatsSpec`](@ref).
 - `verbose::Bool=false`: print the name of each step when it is called.
 - `keep=nothing`: names (of type `Symbol`) of additional objects to be returned.
 - `keepall::Bool=false`: return all objects generated by procedures along with arguments from the [`StatsSpec`](@ref)s.
@@ -683,6 +685,8 @@ macro specset(args...)
         for i in 1:nspec
             sps[i] = StatsSpec($(esc(formatter))(merge($defaults, $args_set[i]))...)
         end
+        # The same args_set will be reused if exectuted again without recalling the macro
+        empty!($args_set)
     end
 
     if noproceed
@@ -693,7 +697,7 @@ macro specset(args...)
     else
         return quote
             $blk
-            proceed(sps; $options...)
+            sps, proceed(sps; $options...)
         end
     end
 end