From 16f2816e812b492df8181fc4fc595b6d760df13a Mon Sep 17 00:00:00 2001
From: Eduardo Bart <edub4rt@gmail.com>
Date: Fri, 4 Sep 2020 09:08:17 -0300
Subject: [PATCH] Make 'arg' semantics more Lua like

---
 lib/allocators/gc.nelua     |  9 +++------
 lib/arg.nelua               | 40 ++++++++++++++++++++-----------------
 lib/string.nelua            |  1 -
 nelua/cgenerator.lua        |  6 +++---
 spec/05-cgenerator_spec.lua | 14 ++++++-------
 spec/08-runner_spec.lua     | 10 ++++++++++
 6 files changed, 45 insertions(+), 35 deletions(-)

diff --git a/lib/allocators/gc.nelua b/lib/allocators/gc.nelua
index 6e4177b3..32b25468 100644
--- a/lib/allocators/gc.nelua
+++ b/lib/allocators/gc.nelua
@@ -531,15 +531,12 @@ function GC:_mark_statics()
   ]]
 end
 
-local function nelua_main(): cint <cimport,nodecl> end
+local function nelua_main(argc: cint, argv: cstring*): cint <cimport,nodecl> end
 
-global arg: span(cstring)
-
-local function main(argc: cint, argv: cchar**): cint <entrypoint>
+local function main(argc: cint, argv: cstring*): cint <entrypoint>
   gc:start(&argc)
   gc:_mark_statics()
-  arg = {data=argv, size=argc}
-  local ret: cint = nelua_main()
+  local ret: cint = nelua_main(argc, argv)
   gc:stop()
   return ret
 end
diff --git a/lib/arg.nelua b/lib/arg.nelua
index 34724210..f8e99903 100644
--- a/lib/arg.nelua
+++ b/lib/arg.nelua
@@ -1,21 +1,25 @@
 -- Include this file to get have the global "arg"
--- with your program command line arguments.
-
-## if pragmas.nogc then
-
-require 'span'
-
-global arg: span(cstring)
-
-local function nelua_main(): cint <cimport,nodecl> end
-
-local function main(argc: cint, argv: cchar**): cint <entrypoint>
-  arg = {data=argv, size=argc}
-  return nelua_main()
+-- filled with your program command line arguments.
+
+require 'sequence'
+require 'allocators.general'
+
+-- Import argc and argv from C 'nelua_main'
+local nelua_argc: cint <cimport, nodecl>
+local nelua_argv: cstring[0]* <cimport, nodecl>
+
+-- List of command line arguments.
+-- The index 0 usually is filled with the program executable.
+-- The arguments goes from 1 up to #arg (like in Lua).
+global arg: sequence(stringview, GeneralAllocator)
+
+do -- setup args
+  local narg: usize = (@usize)(nelua_argc-1)
+  arg:reserve(narg)
+  for i:usize=0,narg do
+    arg[i] = nelua_argv[i]
+  end
 end
 
-## else
-
-require 'allocators.gc'
-
-## end
+-- NOTE: the memory of 'arg' is never freed,
+-- but this is fine, is not a leak for global variables.
diff --git a/lib/string.nelua b/lib/string.nelua
index ae1fc1f4..c9394e47 100644
--- a/lib/string.nelua
+++ b/lib/string.nelua
@@ -50,7 +50,6 @@ function string._create(size: usize): string
   self.data = (@byte[0]*)(string_allocator:alloc(size+1))
   check(self.data ~= nilptr, 'string._create: out of memory')
   self.data[size] = 0
-  --self.refs = 1
   return self
 end
 
diff --git a/nelua/cgenerator.lua b/nelua/cgenerator.lua
index 6bd32d0e..94080120 100644
--- a/nelua/cgenerator.lua
+++ b/nelua/cgenerator.lua
@@ -1400,7 +1400,7 @@ local function emit_main(ast, context)
 
   if not context.entrypoint or context.hookmain then
     mainemitter:inc_indent()
-    mainemitter:add_ln("int nelua_main() {")
+    mainemitter:add_ln("int nelua_main(int nelua_argc, char** nelua_argv) {")
     mainemitter:add_traversal(ast)
     if not context.rootscope.has_return then
       -- main() must always return an integer
@@ -1411,7 +1411,7 @@ local function emit_main(ast, context)
     mainemitter:add_ln("}")
     mainemitter:dec_indent()
 
-    context:add_declaration('int nelua_main();\n')
+    context:add_declaration('int nelua_main(int nelua_argc, char** nelua_argv);\n')
   else
     mainemitter:inc_indent()
     mainemitter:add_traversal(ast)
@@ -1421,7 +1421,7 @@ local function emit_main(ast, context)
   if not context.entrypoint then
     mainemitter:add_indent_ln('int main(int argc, char **argv) {')
     mainemitter:inc_indent(2)
-    mainemitter:add_indent_ln('return nelua_main();')
+    mainemitter:add_indent_ln('return nelua_main(argc, argv);')
     mainemitter:dec_indent(2)
     mainemitter:add_indent_ln('}')
   end
diff --git a/spec/05-cgenerator_spec.lua b/spec/05-cgenerator_spec.lua
index e90b6ed5..a7034f19 100644
--- a/spec/05-cgenerator_spec.lua
+++ b/spec/05-cgenerator_spec.lua
@@ -8,18 +8,18 @@ describe("Nelua should parse and generate C", function()
 
 it("empty file", function()
   assert.generate_c("", [[
-int nelua_main() {
+int nelua_main(int nelua_argc, char** nelua_argv) {
   return 0;
 }]])
 end)
 
 it("return", function()
   assert.generate_c("return", [[
-int nelua_main() {
+int nelua_main(int nelua_argc, char** nelua_argv) {
   return 0;
 }]])
   assert.generate_c("return 1", [[
-int nelua_main() {
+int nelua_main(int nelua_argc, char** nelua_argv) {
   return 1;
 }]])
   assert.generate_c("return 1")
@@ -2061,11 +2061,11 @@ end)
 
 it("hook main", function()
   assert.run_c([[
-    local function nelua_main(): cint <cimport,nodecl> end
-    local function main(argc: cint, argv: cchar**): cint <entrypoint>
+    local function nelua_main(argc: cint, nelua_argv: cstring*): cint <cimport,nodecl> end
+    local function main(argc: cint, argv: cstring*): cint <entrypoint>
       print 'before'
-      local ret = nelua_main()
-      print('after')
+      local ret = nelua_main(argc, argv)
+      print 'after'
       return ret
     end
     print 'inside'
diff --git a/spec/08-runner_spec.lua b/spec/08-runner_spec.lua
index 487fd2dd..b9bcdf8e 100644
--- a/spec/08-runner_spec.lua
+++ b/spec/08-runner_spec.lua
@@ -126,4 +126,14 @@ it("debug options", function()
   ]]}, "scope resolved 1 symbols")
 end)
 
+it("program arguments", function()
+  assert.run({'--eval',[[
+    require 'arg'
+    assert(arg[1] == 'a')
+    assert(arg[2] == 'b')
+    assert(arg[3] == 'c')
+    assert(#arg == 3)
+  ]], 'a', 'b', 'c'})
+end)
+
 end)