Add Show/Hide combinators

Author: xitology

src/FunSQL.jl

@@ -54,6 +54,7 @@ export
     funsql_from,
     funsql_fun,
     funsql_group,
+    funsql_hide,
     funsql_highlight,
     funsql_in,
     funsql_into,
@@ -83,6 +84,7 @@ export
     funsql_rank,
     funsql_row_number,
     funsql_select,
+    funsql_show,
     funsql_sort,
     funsql_sum,
     funsql_with

src/link.jl

@@ -27,13 +27,15 @@ end
 
 function _select(t::RowType)
     refs = SQLQuery[]
+    t.visible || return refs
     for (f, ft) in t.fields
         if ft isa ScalarType
+            ft.visible || continue
             push!(refs, Get(f))
         else
             nested_refs = _select(ft)
             for nested_ref in nested_refs
-                push!(refs, Nested(over = nested_ref, name = f))
+                push!(refs, Nested(name = f, tail = nested_ref))
             end
         end
     end

src/nodes.jl

@@ -54,17 +54,19 @@ terminal(q::SQLQuery) =
 Chain(q′, q) =
     convert(SQLQuery, q)(q′)
 
-label(q::SQLQuery) =
-    @something label(q.head) label(q.tail)
+function label(q::SQLQuery; default = :_)
+    l = label(q.head)
+    l !== nothing ? l : label(q.tail; default)
+end
 
 label(n::AbstractSQLNode) =
     nothing
 
-label(::Nothing) =
-    :_
+label(::Nothing; default = :_) =
+    default
 
-label(q) =
-    label(convert(SQLQuery, q))
+label(q; default = :_) =
+    label(convert(SQLQuery, q); default)
 
 
 # A variant of SQLQuery for assembling a chain of identifiers.
@@ -922,6 +924,7 @@ include("nodes/order.jl")
 include("nodes/over.jl")
 include("nodes/partition.jl")
 include("nodes/select.jl")
+include("nodes/show.jl")
 include("nodes/sort.jl")
 include("nodes/variable.jl")
 include("nodes/where.jl")

src/nodes/internal.jl

@@ -302,7 +302,7 @@ PrettyPrinting.quoteof(n::FunSQLMacroNode, ctx::QuoteContext) =
     Expr(:macrocall, Symbol("@funsql"), n.line, !ctx.limit ? n.ex : :…)
 
 label(n::FunSQLMacroNode) =
-    label(n.query)
+    label(n.query, default = nothing)
 
 
 # Unwrap @funsql macro when displaying the query.

src/nodes/show.jl

@@ -0,0 +1,38 @@
+# Show/Hide nodes
+
+mutable struct ShowNode <: TabularNode
+    names::Vector{Symbol}
+    visible::Bool
+    label_map::FunSQL.OrderedDict{Symbol, Int}
+
+    function ShowNode(; names = [], visible = true, label_map = nothing)
+        if label_map !== nothing
+            new(names, visible, label_map)
+        else
+            n = new(names, visible, FunSQL.OrderedDict{Symbol, Int}())
+            for (i, name) in enumerate(n.names)
+                if name in keys(n.label_map)
+                    err = FunSQL.DuplicateLabelError(name, path = SQLQuery[n])
+                    throw(err)
+                end
+                n.label_map[name] = i
+            end
+            n
+        end
+    end
+end
+
+ShowNode(names...; visible = true) =
+    ShowNode(names = Symbol[names...], visible = visible)
+
+const Show = SQLQueryCtor{ShowNode}(:Show)
+
+Hide(args...; kws...) =
+    Show(args...; kws..., visible = false)
+
+const funsql_show = Show
+const funsql_hide = Hide
+
+function FunSQL.PrettyPrinting.quoteof(n::ShowNode, ctx::QuoteContext)
+    Expr(:call, n.visible ? :Show : :Hide, quoteof(n.names, ctx)...)
+end

src/resolve.jl

@@ -415,7 +415,7 @@ end
 
 function resolve(n::JoinNode, ctx)
     if n.swap
-        ctx′ = ResolveContext(Ctx, tail = n.joinee)
+        ctx′ = ResolveContext(ctx, tail = n.joinee)
         return resolve(JoinNode(joinee = ctx.tail, on = n.on, left = n.right, right = n.left, optional = n.optional), ctx′)
     end
     tail′ = resolve(ctx)
@@ -498,6 +498,33 @@ function resolve(n::SelectNode, ctx)
     Resolved(RowType(fields), tail = q′)
 end
 
+function resolve(n::ShowNode, ctx)
+    tail′ = resolve(ctx)
+    t = row_type(tail′)
+    for name in n.names
+        ft = get(t.fields, name, EmptyType())
+        if ft isa EmptyType
+            throw(
+                ReferenceError(
+                    REFERENCE_ERROR_TYPE.UNDEFINED_NAME,
+                    name = name,
+                    path = get_path(ctx)))
+        end
+    end
+    fields = FieldTypeMap()
+    for (f, ft) in t.fields
+        if f in keys(n.label_map)
+            if ft isa ScalarType
+                ft = ScalarType(visible = n.visible)
+            else
+                ft = RowType(ft.fields, ft.group, visible = n.visible)
+            end
+        end
+        fields[f] = ft
+    end
+    Resolved(RowType(fields, t.group, visible = t.visible), tail = tail′)
+end
+
 function resolve_scalar(n::SortNode, ctx)
     tail′ = resolve_scalar(ctx)
     q′ = Sort(value = n.value, nulls = n.nulls, tail = tail′)

src/types.jl

@@ -13,17 +13,27 @@ PrettyPrinting.quoteof(::EmptyType) =
     Expr(:call, nameof(EmptyType))
 
 struct ScalarType <: AbstractSQLType
+    visible::Bool
+
+    ScalarType(; visible = true) =
+        new(visible)
 end
 
-PrettyPrinting.quoteof(::ScalarType) =
-    Expr(:call, nameof(ScalarType))
+function PrettyPrinting.quoteof(t::ScalarType)
+    ex = Expr(:call, nameof(ScalarType))
+    if !t.visible
+        push!(ex.args, Expr(:kw, :visible, t.visible))
+    end
+    ex
+end
 
 struct RowType <: AbstractSQLType
     fields::OrderedDict{Symbol, Union{ScalarType, RowType}}
     group::Union{EmptyType, RowType}
+    visible::Bool
 
-    RowType(fields, group = EmptyType()) =
-        new(fields, group)
+    RowType(fields, group = EmptyType(); visible = true) =
+        new(fields, group, visible)
 end
 
 const FieldTypeMap = OrderedDict{Symbol, Union{ScalarType, RowType}}
@@ -43,6 +53,9 @@ function PrettyPrinting.quoteof(t::RowType)
     if !(t.group isa EmptyType)
         push!(ex.args, Expr(:kw, :group, quoteof(t.group)))
     end
+    if !t.visible
+        push!(ex.args, Expr(:kw, :visible, t.visible))
+    end
     ex
 end
 
@@ -54,8 +67,8 @@ const EMPTY_ROW = RowType()
 Base.intersect(::AbstractSQLType, ::AbstractSQLType) =
     EmptyType()
 
-Base.intersect(::ScalarType, ::ScalarType) =
-    ScalarType()
+Base.intersect(t1::ScalarType, t2::ScalarType) =
+    ScalarType(visible = t1.visible || t2.visible)
 
 function Base.intersect(t1::RowType, t2::RowType)
     if t1 === t2
@@ -71,7 +84,7 @@ function Base.intersect(t1::RowType, t2::RowType)
         end
     end
     group = intersect(t1.group, t2.group)
-    RowType(fields, group)
+    RowType(fields, group, visible = t1.visible || t2.visible)
 end
 
 
@@ -98,5 +111,8 @@ function Base.issubset(t1::RowType, t2::RowType)
     if !issubset(t1.group, t2.group)
         return false
     end
+    if !t1.visible && t2.visible
+        return false
+    end
     return true
 end