let set default value for function parameters

doc/COMPATIBILITY.md

@@ -48,7 +48,7 @@ Features
     - [x] insensitive name of functions
     - [x] call to functions
     - [x] args by reference
-    - [ ] default values as params in functions
+    - [x] default values as params in functions
     - [x] include/require code from other files
 - Error handling
     - [x] launch errors

include/ephp.hrl

@@ -219,6 +219,7 @@
     class :: class_name() | undefined,
     name :: binary(),
     idx = [] :: [array_index() | {object, binary()} | {class, binary()}],
+    default_value = null :: mixed(),
     line :: line()
 }).
 
@@ -302,7 +303,7 @@
     name :: binary(),
     access = public :: access_types(),
     type = normal :: normal | static,
-    init_value = null :: any()
+    init_value = null :: mixed()
 }).
 
 -type class_attr() :: #class_attr{}.

src/ephp_context.erl

@@ -517,9 +517,10 @@ resolve(#array{elements=ArrayElements}, State) ->
 resolve(#concat{texts=Texts}, State) ->
     resolve_txt(Texts, State);
 
-resolve(#call{name=#function{args=FuncArgs,code=Code,use=Use},args=RawArgs},
+resolve(#call{name=#function{args=RawFuncArgs,code=Code,use=Use},args=RawArgs},
         #state{ref=Ref,vars=Vars,const=Const}=State) ->
-    {Args, NState} = resolve_args(RawArgs, State),
+    {Args, NStatePrev} = resolve_args(RawArgs, State),
+    {FuncArgs, NState} = resolve_func_args(RawFuncArgs, NStatePrev),
     {ok, NewVars} = ephp_vars:start_link(),
     {ok, SubContext} = start_mirror(NState#state{
         vars=NewVars,
@@ -570,8 +571,9 @@ resolve(#call{type=normal,name=Fun,args=RawArgs,line=Index}=_Call,
         end,
         destroy(Mirror),
         {Value, NState};
-    {ok,#reg_func{type=php, args=FuncArgs, code=Code}} ->
-        {Args, NState} = resolve_args(RawArgs, State),
+    {ok,#reg_func{type=php, args=RawFuncArgs, code=Code}} ->
+        {Args, NStatePrev} = resolve_args(RawArgs, State),
+        {FuncArgs, NState} = resolve_func_args(RawFuncArgs, NStatePrev),
         {ok, NewVars} = ephp_vars:start_link(),
         {ok, SubContext} = start_mirror(NState#state{
             vars=NewVars,
@@ -671,6 +673,15 @@ resolve(#function{name=undefined,use=Use}=Anon, #state{vars=Vars}=State) ->
 resolve(Unknown, _State) ->
     ephp_error:error({error, eundeftoken, undefined, ?E_CORE_ERROR, Unknown}).
 
+resolve_func_args(RawFuncArgs, State) ->
+    lists:foldl(fun
+        (#variable{default_value=Val}=Var, {Vars, S}) when Val =/= null ->
+            {Value, NewState} = resolve(Val,S),
+            {Vars ++ [Var#variable{default_value=Value}], NewState};
+        (Var, {Vars, NewState}) ->
+            {Vars ++ [Var], NewState}
+    end, {[], State}, RawFuncArgs).
+
 resolve_args(RawArgs, State) ->
     lists:foldl(fun(Arg, {Args,S}) ->
         {A,NewState} = resolve(Arg,S),

src/ephp_parser.peg

@@ -418,7 +418,14 @@ st_if_simple <- if space? conditions_use space? ( code_block / statement / error
     end, line=Index}
 `;
 
-st_function <- function space key space? '(' space? (var (space? ',' space? var)*
+param <- var (space? '=' space? expression)? `
+    case Node of
+        [Var,[]] -> Var;
+        [Var,[_,_,_,Expression]] -> Var#variable{default_value=Expression}
+    end
+`;
+
+st_function <- function space key space? '(' space? (param (space? ',' space? param)*
                space?)? ')' space? code_block
 `
     case Node of

src/ephp_vars.erl

@@ -59,6 +59,9 @@ zip_args(VarsSrc, VarsDst, ValArgs, FuncArgs) ->
         (FuncArg, [{_,ArgVal}|RestArgs]) ->
             set(VarsDst, FuncArg, ArgVal),
             RestArgs;
+        (#variable{default_value=Val}=FuncArg, []) when Val =/= null ->
+            set(VarsDst, FuncArg, Val),
+            [];
         (_FuncArg, []) ->
             []
     end, ValArgs, FuncArgs),

test/code/test_func_default_params.out

@@ -0,0 +1,3 @@
+Hi mum!
+Hello world
+hello world

test/code/test_func_default_params.php

@@ -0,0 +1,10 @@
+<?php
+
+function show($greeting='hello', $who='world') {
+    print $greeting . " " . $who . "\n";
+}
+
+print show("Hi", "mum!");
+print show("Hello");
+print show();
+