1 files changed, 106 insertions, 0 deletions
diff --git a/script/core/signature.lua b/script/core/signature.lua
new file mode 100644
index 00000000..dad38924
--- /dev/null
+++ b/script/core/signature.lua
@@ -0,0 +1,106 @@
+local files      = require 'files'
+local guide      = require 'parser.guide'
+local vm         = require 'vm'
+local hoverLabel = require 'core.hover.label'
+local hoverDesc  = require 'core.hover.description'
+
+local function findNearCall(uri, ast, pos)
+    local text = files.getText(uri)
+    -- 检查 `f()$` 的情况，注意要区别于 `f($`
+    if text:sub(pos, pos) == ')' then
+        return nil
+    end
+
+    local nearCall
+    guide.eachSourceContain(ast.ast, pos, function (src)
+        if src.type == 'call'
+        or src.type == 'table'
+        or src.type == 'function' then
+            if not nearCall or nearCall.start < src.start then
+                nearCall = src
+            end
+        end
+    end)
+    if not nearCall then
+        return nil
+    end
+    if nearCall.type ~= 'call' then
+        return nil
+    end
+    return nearCall
+end
+
+local function makeOneSignature(source, oop, index)
+    local label = hoverLabel(source, oop)
+    -- 去掉返回值
+    label = label:gsub('%s*->.+', '')
+    local params = {}
+    local i = 0
+    for start, finish in label:gmatch '[%(%)%,]%s*().-()%s*%f[%(%)%,%[%]]' do
+        i = i + 1
+        params[i] = {
+            label = {start, finish-1},
+        }
+    end
+    -- 不定参数
+    if index > i and i > 0 then
+        local lastLabel = params[i].label
+        local text = label:sub(lastLabel[1], lastLabel[2])
+        if text == '...' then
+            index = i
+        end
+    end
+    return {
+        label       = label,
+        params      = params,
+        index       = index,
+        description = hoverDesc(source),
+    }
+end
+
+local function makeSignatures(call, pos)
+    local node = call.node
+    local oop = node.type == 'method'
+             or node.type == 'getmethod'
+             or node.type == 'setmethod'
+    local index
+    local args = call.args
+    if args then
+        for i, arg in ipairs(args) do
+            if arg.start <= pos and arg.finish >= pos then
+                index = i
+                break
+            end
+        end
+        if not index then
+            index = #args + 1
+        end
+    else
+        index = 1
+    end
+    local signs = {}
+    local defs = vm.getDefs(node, 'deep')
+    for _, src in ipairs(defs) do
+        if src.type == 'function'
+        or src.type == 'doc.type.function' then
+            signs[#signs+1] = makeOneSignature(src, oop, index)
+        end
+    end
+    return signs
+end
+
+return function (uri, pos)
+    local ast = files.getAst(uri)
+    if not ast then
+        return nil
+    end
+    local call = findNearCall(uri, ast, pos)
+    if not call then
+        return nil
+    end
+    local signs = makeSignatures(call, pos)
+    if not signs or #signs == 0 then
+        return nil
+    end
+    return signs
+end