#!/bin/bash

# If this file has already been sourced, just return
test $(SPECIALFORMS_IF_SH+true)TODO  && return
declare -g SPECIALFORMS_IF_SH = 'true'

source ${BASH_SOURCE%/*}/common.sh
source ${BASH_SOURCE%/*}/test.sh
source ${BASH_SOURCE%/*}/specialforms.sh

#
# IF
#
# Predicate, consequent, and alternative are expressions. An if expression is
# evaluated as follows: first, predicate is evaluated. If it yields a true
# value, then consequent is evaluated and its value is returned. Otherwise
# alternative is evaluated and its value is returned. If predicate yields a
# false value and no alternative is specified, then the result of the expression
# is unspecified.
#
# An if expression evaluates either consequent or alternative, never
# both. Programs should not depend on the value of an if expression that has no
# alternative.
#
# (if (> 3 2) 'yes 'no)                   =>  yes
# (if (> 2 3) 'yes 'no)                   =>  no
# (if (> 3 2)
#     (- 3 2)
#     (+ 3 2))                            =>  1
#
proc evaluator::specialforms::ifTODO  {
    declare env = $(1)TODO 
    declare functionName = $(2)TODO  # if
    declare args = $(3) # list of condition, <true branch>, <false branch>

    variable::LinkedList::length $argsTODO  ; declare -i length = $(RESULT)
    if [[ $length != 3 ]] {
        stderr "usage: (if condition true-branch false-branch)"
        exit 1
    }

    variable::LinkedList::index $args 0TODO  ; declare condition = $(RESULT)
    variable::LinkedList::index $args 1TODO  ; declare trueBranch = $(RESULT)
    variable::LinkedList::index $args 2TODO  ; declare falseBranch = $(RESULT)

    evaluator::eval $env $conditionTODO  ; declare conditionResult = $(RESULT)
    variable::type::instanceOfOrExit $conditionResult Boolean

    variable::value $conditionResult
    if [[ "true" == "${RESULT}" ]] {
        evaluator::eval $env $trueBranch
    } else {
        evaluator::eval $env $falseBranch
    }
    global RESULT := $(RESULT)
}



# 
# ======================================================
if test $0 != $BASH_SOURCE {
    return
}

#
# TRUE
#
#
# not using env
#
createTestEnv ; global env := $(RESULT)
variable::LinkedList::new ; global command := $(RESULT)
appendToList $command Identifier "if"

variable::LinkedList::new ; global conditional := $(RESULT)
appendToList $conditional Identifier "=" Integer 3 Integer 3
variable::LinkedList::append $command $conditional

appendToList $command String yes String no

evaluator::eval $env $command
variable::debug $(RESULT) ; \
    assert::equals "String :: yes" $(RESULT) "(if (= 3 3) 'yes 'no)"


#
# FALSE
# 
createTestEnv ; global env := $(RESULT)
variable::LinkedList::new ; global command := $(RESULT)
appendToList $command Identifier "if"

variable::LinkedList::new ; global conditional := $(RESULT)
appendToList $conditional Identifier "=" Integer 3 Integer 4
variable::LinkedList::append $command $conditional

appendToList $command String yes String no

evaluator::eval $env $command
variable::debug $(RESULT) ; \
    assert::equals "String :: no" $(RESULT) "(if (= 3 4) 'yes 'no)"


#
# Evaluates result
#
createTestEnv ; global env := $(RESULT)
setInEnv $env "v" Integer 10
variable::LinkedList::new ; global command := $(RESULT)
appendToList $command Identifier "if"

variable::LinkedList::new ; global conditional := $(RESULT)
appendToList $conditional Identifier "=" Integer 3 Integer 4
variable::LinkedList::append $command $conditional

appendToList $command Integer 5 Identifier v

evaluator::eval $env $command
variable::debug $(RESULT) ; \
    assert::equals "Integer :: 10" $(RESULT) "(if (= 3 4) 'yes 'no)"



assert::report

if test $(1+isset) && test $1 == "debug" { 
    variable::printMetadata
}

(CommandList
  children: [
    (AndOr
      children: [
        (C {(Lit_Other "[")} 
          {
            (BracedVarSub
              token: <VSub_Name SPECIALFORMS_IF_SH>
              suffix_op: (StringUnary op_id:VTest_Plus arg_word:{(true)})
              spids: [9 13]
            )
          } {(Lit_Other "]")}
        )
        (ControlFlow token:<ControlFlow_Return return>)
      ]
      op_id: Op_DAmp
    )
    (Assignment
      keyword: Assign_Declare
      flags: ["'-g'"]
      pairs: [(assign_pair lhs:(LhsName name:SPECIALFORMS_IF_SH) op:Equal rhs:{(true)} spids:[25])]
      spids: [21]
    )
    (C {(.)} 
      {
        (BracedVarSub
          token: <VSub_Name BASH_SOURCE>
          suffix_op: (StringUnary op_id:VOp1_Percent arg_word:{(Lit_Slash /) ("*")})
          spids: [31 36]
        ) (/common.sh)
      }
    )
    (C {(.)} 
      {
        (BracedVarSub
          token: <VSub_Name BASH_SOURCE>
          suffix_op: (StringUnary op_id:VOp1_Percent arg_word:{(Lit_Slash /) ("*")})
          spids: [41 46]
        ) (/test.sh)
      }
    )
    (C {(.)} 
      {
        (BracedVarSub
          token: <VSub_Name BASH_SOURCE>
          suffix_op: (StringUnary op_id:VOp1_Percent arg_word:{(Lit_Slash /) ("*")})
          spids: [51 56]
        ) (/specialforms.sh)
      }
    )
    (FuncDef
      name: "evaluator::specialforms::if"
      body: 
        (BraceGroup
          children: [
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:env)
                  op: Equal
                  rhs: {(DQ (${ VSub_Number 1))}
                  spids: [137]
                )
              ]
              spids: [135]
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:functionName)
                  op: Equal
                  rhs: {(DQ (${ VSub_Number 2))}
                  spids: [147]
                )
              ]
              spids: [145]
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:args)
                  op: Equal
                  rhs: {(DQ (${ VSub_Number 3))}
                  spids: [160]
                )
              ]
              spids: [158]
            )
            (Sentence
              child: 
                (C 
                  {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") 
                    (Lit_Other ":") (length)
                  } {($ VSub_Name "$args")}
                )
              terminator: <Op_Semi ";">
            )
            (Assignment
              keyword: Assign_Declare
              flags: ["'-i'"]
              pairs: [
                (assign_pair
                  lhs: (LhsName name:length)
                  op: Equal
                  rhs: {(DQ (${ VSub_Name RESULT))}
                  spids: [188]
                )
              ]
              spids: [184]
            )
            (If
              arms: [
                (if_arm
                  cond: [
                    (Sentence
                      child: 
                        (DBracket
                          expr: 
                            (BoolBinary
                              op_id: BoolBinary_GlobNEqual
                              left: {($ VSub_Name "$length")}
                              right: {(3)}
                            )
                        )
                      terminator: <Op_Semi ";">
                    )
                  ]
                  action: [
                    (C {(stderr)} {(DQ ("usage: (if condition true-branch false-branch)"))})
                    (C {(exit)} {(1)})
                  ]
                  spids: [-1 209]
                )
              ]
              spids: [-1 224]
            )
            (Sentence
              child: 
                (C 
                  {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") 
                    (Lit_Other ":") (index)
                  } {($ VSub_Name "$args")} {(0)}
                )
              terminator: <Op_Semi ";">
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:condition)
                  op: Equal
                  rhs: {(${ VSub_Name RESULT)}
                  spids: [244]
                )
              ]
              spids: [242]
            )
            (Sentence
              child: 
                (C 
                  {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") 
                    (Lit_Other ":") (index)
                  } {($ VSub_Name "$args")} {(1)}
                )
              terminator: <Op_Semi ";">
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:trueBranch)
                  op: Equal
                  rhs: {(${ VSub_Name RESULT)}
                  spids: [266]
                )
              ]
              spids: [264]
            )
            (Sentence
              child: 
                (C 
                  {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") 
                    (Lit_Other ":") (index)
                  } {($ VSub_Name "$args")} {(2)}
                )
              terminator: <Op_Semi ";">
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:falseBranch)
                  op: Equal
                  rhs: {(${ VSub_Name RESULT)}
                  spids: [288]
                )
              ]
              spids: [286]
            )
            (Sentence
              child: 
                (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
                  {($ VSub_Name "$condition")}
                )
              terminator: <Op_Semi ";">
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:conditionResult)
                  op: Equal
                  rhs: {(${ VSub_Name RESULT)}
                  spids: [308]
                )
              ]
              spids: [306]
            )
            (C 
              {(variable) (Lit_Other ":") (Lit_Other ":") (type) (Lit_Other ":") (Lit_Other ":") 
                (instanceOfOrExit)
              } {($ VSub_Name "$conditionResult")} {(Boolean)}
            )
            (C {(variable) (Lit_Other ":") (Lit_Other ":") (value)} {($ VSub_Name "$conditionResult")})
            (If
              arms: [
                (if_arm
                  cond: [
                    (Sentence
                      child: 
                        (DBracket
                          expr: 
                            (BoolBinary
                              op_id: BoolBinary_GlobDEqual
                              left: {(DQ (true))}
                              right: {(DQ (${ VSub_Name RESULT))}
                            )
                        )
                      terminator: <Op_Semi ";">
                    )
                  ]
                  action: [
                    (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
                      {($ VSub_Name "$trueBranch")}
                    )
                  ]
                  spids: [-1 355]
                )
              ]
              else_action: [
                (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
                  {($ VSub_Name "$falseBranch")}
                )
              ]
              spids: [368 381]
            )
            (Assignment
              keyword: Assign_None
              pairs: [
                (assign_pair
                  lhs: (LhsName name:RESULT)
                  op: Equal
                  rhs: {(DQ (${ VSub_Name RESULT))}
                  spids: [384]
                )
              ]
              spids: [384]
            )
          ]
          spids: [132]
        )
      spids: [120 131]
    )
    (If
      arms: [
        (if_arm
          cond: [
            (Sentence
              child: 
                (C {(Lit_Other "[")} {($ VSub_Number "$0")} {(KW_Bang "!") (Lit_Other "=")} 
                  {($ VSub_Name "$BASH_SOURCE")} {(Lit_Other "]")}
                )
              terminator: <Op_Semi ";">
            )
          ]
          action: [(ControlFlow token:<ControlFlow_Return return>)]
          spids: [-1 416]
        )
      ]
      spids: [-1 421]
    )
    (Sentence child:(C {(createTestEnv)}) terminator:<Op_Semi ";">)
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:env)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [446]
        )
      ]
      spids: [446]
    )
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:command)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [463]
        )
      ]
      spids: [463]
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(DQ (if))})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:conditional)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [491]
        )
      ]
      spids: [491]
    )
    (C {(appendToList)} {($ VSub_Name "$conditional")} {(Identifier)} {(DQ ("="))} {(Integer)} {(3)} 
      {(Integer)} {(3)}
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$conditional")}
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(String)} {(yes)} {(String)} {(no)})
    (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
      {($ VSub_Name "$command")}
    )
    (Sentence
      child: (C {(variable) (Lit_Other ":") (Lit_Other ":") (debug)} {(DQ (${ VSub_Name RESULT))})
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {(DQ ("String :: yes"))} 
      {(DQ (${ VSub_Name RESULT))} {(DQ ("(if (= 3 3) 'yes 'no)"))}
    )
    (Sentence child:(C {(createTestEnv)}) terminator:<Op_Semi ";">)
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:env)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [600]
        )
      ]
      spids: [600]
    )
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:command)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [617]
        )
      ]
      spids: [617]
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(DQ (if))})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:conditional)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [645]
        )
      ]
      spids: [645]
    )
    (C {(appendToList)} {($ VSub_Name "$conditional")} {(Identifier)} {(DQ ("="))} {(Integer)} {(3)} 
      {(Integer)} {(4)}
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$conditional")}
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(String)} {(yes)} {(String)} {(no)})
    (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
      {($ VSub_Name "$command")}
    )
    (Sentence
      child: (C {(variable) (Lit_Other ":") (Lit_Other ":") (debug)} {(DQ (${ VSub_Name RESULT))})
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {(DQ ("String :: no"))} 
      {(DQ (${ VSub_Name RESULT))} {(DQ ("(if (= 3 4) 'yes 'no)"))}
    )
    (Sentence child:(C {(createTestEnv)}) terminator:<Op_Semi ";">)
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:env)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [754]
        )
      ]
      spids: [754]
    )
    (C {(setInEnv)} {($ VSub_Name "$env")} {(DQ (v))} {(Integer)} {(10)})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:command)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [783]
        )
      ]
      spids: [783]
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(DQ (if))})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:conditional)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [811]
        )
      ]
      spids: [811]
    )
    (C {(appendToList)} {($ VSub_Name "$conditional")} {(Identifier)} {(DQ ("="))} {(Integer)} {(3)} 
      {(Integer)} {(4)}
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$conditional")}
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Integer)} {(5)} {(Identifier)} {(v)})
    (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
      {($ VSub_Name "$command")}
    )
    (Sentence
      child: (C {(variable) (Lit_Other ":") (Lit_Other ":") (debug)} {(DQ (${ VSub_Name RESULT))})
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {(DQ ("Integer :: 10"))} 
      {(DQ (${ VSub_Name RESULT))} {(DQ ("(if (= 3 4) 'yes 'no)"))}
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (report)})
    (If
      arms: [
        (if_arm
          cond: [
            (Sentence
              child: 
                (AndOr
                  children: [
                    (C {(Lit_Other "[")} 
                      {
                        (BracedVarSub
                          token: <VSub_Number 1>
                          suffix_op: (StringUnary op_id:VTest_Plus arg_word:{(isset)})
                          spids: [918 922]
                        )
                      } {(Lit_Other "]")}
                    )
                    (C {(Lit_Other "[")} {(DQ ($ VSub_Number "$1"))} {(Lit_Other "=") (Lit_Other "=")} 
                      {(DQ (debug))} {(Lit_Other "]")}
                    )
                  ]
                  op_id: Op_DAmp
                )
              terminator: <Op_Semi ";">
            )
          ]
          action: [(C {(variable) (Lit_Other ":") (Lit_Other ":") (printMetadata)})]
          spids: [-1 944]
        )
      ]
      spids: [-1 953]
    )
  ]
)