#!/bin/bash

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

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

#
# LAMBDA
# (lambda formals expression expression ..._)
#
# A lambda expression evaluates to a procedure. The environment in effect when
# the lambda expression is evaluated is remembered as part of the procedure; it
# is called the closing environment. When the procedure is later called with
# some arguments, the closing environment is extended by binding the variables
# in the formal parameter list to fresh locations, and the locations are filled
# with the arguments according to rules about to be given. The new environment
# created by this process is referred to as the invocation environment.
#
# Once the invocation environment has been constructed, the expressions in the
# body of the lambda expression are evaluated sequentially in it. This means
# that the region of the variables bound by the lambda expression is all of the
# expressions in the body. The result of evaluating the last expression in the
# body is returned as the result of the procedure call.
#
#
#
proc evaluator::specialforms::lambdaTODO  {
    declare env = $(1)TODO 
    declare functionName = $(2)TODO  # if
    declare args = $(3) # list of <formal args list>, <expression>,...,<expression>

    variable::LinkedList::length $argsTODO  ; declare -i length = $(RESULT)
    if [[ $length < 2 ]] {
        stderr "usage: (if condition true-branch false-branch)"
        exit 1
    }

    variable::LinkedList::first $argsTODO  ; declare formalArgs = $(RESULT)
    variable::LinkedList::rest $argsTODO  ; declare expressions = $(RESULT)

    variable::Lambda::new "$(env) $(formalArgs) $(expressions)"
    global RESULT := $(RESULT)
}



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

#
# no args
# (lambda () 1)
#
createTestEnv ; global env := $(RESULT)
variable::LinkedList::new ; global command := $(RESULT)
appendToList $command Identifier "lambda" 

variable::LinkedList::new ;
variable::LinkedList::append $command $RESULT

appendToList $command Integer 1

evaluator::eval $env $command ; global lambda := $(RESULT)
variable::toSexp $(lambda) ; \
    assert::equals "(lambda () 1)" $(RESULT) "(lambda () 1)"
variable::Lambda::getEnv $lambda ; \
    assert::equals $env $RESULT "<original env> = <stored env>"

#
# with args
# (lambda (a b c) 1)
#
createTestEnv ; global env := $(RESULT)
variable::LinkedList::new ; global command := $(RESULT)
appendToList $command Identifier "lambda" 

variable::LinkedList::new ; global argList := $(RESULT)
appendToList $(argList) Identifier a Identifier b Identifier c
variable::LinkedList::append $command $argList

appendToList $command Integer 1

evaluator::eval $env $command ; global lambda := $(RESULT)
variable::toSexp $(lambda) ; \
    assert::equals "(lambda (a b c) 1)" $(RESULT) "(lambda (a b c) 1)"

#
# multiple commands
# (lambda () x y)
#
createTestEnv ; global env := $(RESULT)
variable::LinkedList::new ; global command := $(RESULT)
appendToList $command Identifier "lambda" 

variable::LinkedList::new ;
variable::LinkedList::append $command $RESULT

appendToList $command Identifier x Identifier y

evaluator::eval $env $command ; global lambda := $(RESULT)
variable::toSexp $(lambda) ; \
    assert::equals "(lambda () x y)" $(RESULT) "(lambda () x y)"

#
# multiple commands as lists
# (lambda () (+ 1 2) (+ 2 3))
#
createTestEnv ; global env := $(RESULT)
variable::LinkedList::new ; global command := $(RESULT)
appendToList $command Identifier "lambda" 

variable::LinkedList::new ;
variable::LinkedList::append $command $RESULT

variable::LinkedList::new ; global sc1 := $(RESULT)
appendToList $sc1 Identifier + Integer 1 Integer 2
variable::LinkedList::append $command $sc1

variable::LinkedList::new ; global sc2 := $(RESULT)
appendToList $sc2 Identifier + Integer 2 Integer 3
variable::LinkedList::append $command $sc2

evaluator::eval $env $command ; global lambda := $(RESULT)
variable::toSexp $(lambda) ; \
    assert::equals "(lambda () (+ 1 2) (+ 2 3))" $(RESULT) "(lambda () (+ 1 2) (+ 2 3))"




assert::report

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

(CommandList
  children: [
    (AndOr
      children: [
        (C {(Lit_Other "[")} 
          {
            (BracedVarSub
              token: <VSub_Name SPECIALFORMS_LAMBDA_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_LAMBDA_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)
      }
    )
    (C {(.)} 
      {
        (BracedVarSub
          token: <VSub_Name BASH_SOURCE>
          suffix_op: (StringUnary op_id:VOp1_Percent arg_word:{(Lit_Slash /) ("*")})
          spids: [61 66]
        ) (/callable.lambda.sh)
      }
    )
    (FuncDef
      name: "evaluator::specialforms::lambda"
      body: 
        (BraceGroup
          children: [
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:env)
                  op: Equal
                  rhs: {(DQ (${ VSub_Number 1))}
                  spids: [147]
                )
              ]
              spids: [145]
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:functionName)
                  op: Equal
                  rhs: {(DQ (${ VSub_Number 2))}
                  spids: [157]
                )
              ]
              spids: [155]
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:args)
                  op: Equal
                  rhs: {(DQ (${ VSub_Number 3))}
                  spids: [170]
                )
              ]
              spids: [168]
            )
            (Sentence
              child: 
                (C 
                  {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") 
                    (Lit_Other ":") (length)
                  } {($ 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: [198]
                )
              ]
              spids: [194]
            )
            (If
              arms: [
                (if_arm
                  cond: [
                    (Sentence
                      child: 
                        (DBracket
                          expr: 
                            (BoolBinary
                              op_id: Redir_Less
                              left: {($ VSub_Name "$length")}
                              right: {(2)}
                            )
                        )
                      terminator: <Op_Semi ";">
                    )
                  ]
                  action: [
                    (C {(stderr)} {(DQ ("usage: (if condition true-branch false-branch)"))})
                    (C {(exit)} {(1)})
                  ]
                  spids: [-1 219]
                )
              ]
              spids: [-1 234]
            )
            (Sentence
              child: 
                (C 
                  {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") 
                    (Lit_Other ":") (first)
                  } {($ VSub_Name "$args")}
                )
              terminator: <Op_Semi ";">
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:formalArgs)
                  op: Equal
                  rhs: {(${ VSub_Name RESULT)}
                  spids: [252]
                )
              ]
              spids: [250]
            )
            (Sentence
              child: 
                (C 
                  {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") 
                    (Lit_Other ":") (rest)
                  } {($ VSub_Name "$args")}
                )
              terminator: <Op_Semi ";">
            )
            (Assignment
              keyword: Assign_Declare
              pairs: [
                (assign_pair
                  lhs: (LhsName name:expressions)
                  op: Equal
                  rhs: {(${ VSub_Name RESULT)}
                  spids: [272]
                )
              ]
              spids: [270]
            )
            (C 
              {(variable) (Lit_Other ":") (Lit_Other ":") (Lambda) (Lit_Other ":") (Lit_Other ":") (new)} {(DQ (${ VSub_Name env) (" ") (${ VSub_Name formalArgs) (" ") (${ VSub_Name expressions))}
            )
            (Assignment
              keyword: Assign_None
              pairs: [
                (assign_pair
                  lhs: (LhsName name:RESULT)
                  op: Equal
                  rhs: {(DQ (${ VSub_Name RESULT))}
                  spids: [302]
                )
              ]
              spids: [302]
            )
          ]
          spids: [142]
        )
      spids: [130 141]
    )
    (If
      arms: [
        (if_arm
          cond: [
            (Sentence
              child: 
                (C {(Lit_Other "[")} {($ VSub_Number "$0")} {(KW_Bang "!") (Lit_Other "=")} 
                  {($ VSub_Name "$BASH_SOURCE")} {(Lit_Other "]")}
                )
              terminator: <Op_Semi ";">
            )
          ]
          action: [(ControlFlow token:<ControlFlow_Return return>)]
          spids: [-1 334]
        )
      ]
      spids: [-1 339]
    )
    (Sentence child:(C {(createTestEnv)}) terminator:<Op_Semi ";">)
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:env)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [358]
        )
      ]
      spids: [358]
    )
    (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 (${ VSub_Name RESULT))}
          spids: [375]
        )
      ]
      spids: [375]
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(DQ (lambda))})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$RESULT")}
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Integer)} {(1)})
    (Sentence
      child: 
        (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
          {($ VSub_Name "$command")}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:lambda)
          op: Equal
          rhs: {(${ VSub_Name RESULT)}
          spids: [437]
        )
      ]
      spids: [437]
    )
    (Sentence
      child: (C {(variable) (Lit_Other ":") (Lit_Other ":") (toSexp)} {(DQ (${ VSub_Name lambda))})
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {(DQ ("(lambda () 1)"))} 
      {(DQ (${ VSub_Name RESULT))} {(DQ ("(lambda () 1)"))}
    )
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (Lambda) (Lit_Other ":") (Lit_Other ":") (getEnv)} {($ VSub_Name "$lambda")}
        )
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {($ VSub_Name "$env")} 
      {($ VSub_Name "$RESULT")} {(DQ ("<original env> = <stored env>"))}
    )
    (Sentence child:(C {(createTestEnv)}) terminator:<Op_Semi ";">)
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:env)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [520]
        )
      ]
      spids: [520]
    )
    (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 (${ VSub_Name RESULT))}
          spids: [537]
        )
      ]
      spids: [537]
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(DQ (lambda))})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:argList)
          op: Equal
          rhs: {(${ VSub_Name RESULT)}
          spids: [566]
        )
      ]
      spids: [566]
    )
    (C {(appendToList)} {(${ VSub_Name argList)} {(Identifier)} {(a)} {(Identifier)} {(b)} {(Identifier)} 
      {(c)}
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$argList")}
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Integer)} {(1)})
    (Sentence
      child: 
        (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
          {($ VSub_Name "$command")}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:lambda)
          op: Equal
          rhs: {(${ VSub_Name RESULT)}
          spids: [622]
        )
      ]
      spids: [622]
    )
    (Sentence
      child: (C {(variable) (Lit_Other ":") (Lit_Other ":") (toSexp)} {(DQ (${ VSub_Name lambda))})
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {(DQ ("(lambda (a b c) 1)"))} 
      {(DQ (${ VSub_Name RESULT))} {(DQ ("(lambda (a b c) 1)"))}
    )
    (Sentence child:(C {(createTestEnv)}) terminator:<Op_Semi ";">)
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:env)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [678]
        )
      ]
      spids: [678]
    )
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:command)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [695]
        )
      ]
      spids: [695]
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(DQ (lambda))})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$RESULT")}
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(x)} {(Identifier)} {(y)})
    (Sentence
      child: 
        (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
          {($ VSub_Name "$command")}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:lambda)
          op: Equal
          rhs: {(${ VSub_Name RESULT)}
          spids: [761]
        )
      ]
      spids: [761]
    )
    (Sentence
      child: (C {(variable) (Lit_Other ":") (Lit_Other ":") (toSexp)} {(DQ (${ VSub_Name lambda))})
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {(DQ ("(lambda () x y)"))} 
      {(DQ (${ VSub_Name RESULT))} {(DQ ("(lambda () x y)"))}
    )
    (Sentence child:(C {(createTestEnv)}) terminator:<Op_Semi ";">)
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:env)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [817]
        )
      ]
      spids: [817]
    )
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:command)
          op: Equal
          rhs: {(DQ (${ VSub_Name RESULT))}
          spids: [834]
        )
      ]
      spids: [834]
    )
    (C {(appendToList)} {($ VSub_Name "$command")} {(Identifier)} {(DQ (lambda))})
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$RESULT")}
    )
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [(assign_pair lhs:(LhsName name:sc1) op:Equal rhs:{(${ VSub_Name RESULT)} spids:[886])]
      spids: [886]
    )
    (C {(appendToList)} {($ VSub_Name "$sc1")} {(Identifier)} {(Lit_Other "+")} {(Integer)} {(1)} 
      {(Integer)} {(2)}
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$sc1")}
    )
    (Sentence
      child: 
        (C 
          {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (new)}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [(assign_pair lhs:(LhsName name:sc2) op:Equal rhs:{(${ VSub_Name RESULT)} spids:[930])]
      spids: [930]
    )
    (C {(appendToList)} {($ VSub_Name "$sc2")} {(Identifier)} {(Lit_Other "+")} {(Integer)} {(2)} 
      {(Integer)} {(3)}
    )
    (C 
      {(variable) (Lit_Other ":") (Lit_Other ":") (LinkedList) (Lit_Other ":") (Lit_Other ":") (append)} {($ VSub_Name "$command")} {($ VSub_Name "$sc2")}
    )
    (Sentence
      child: 
        (C {(evaluator) (Lit_Other ":") (Lit_Other ":") (eval)} {($ VSub_Name "$env")} 
          {($ VSub_Name "$command")}
        )
      terminator: <Op_Semi ";">
    )
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:lambda)
          op: Equal
          rhs: {(${ VSub_Name RESULT)}
          spids: [975]
        )
      ]
      spids: [975]
    )
    (Sentence
      child: (C {(variable) (Lit_Other ":") (Lit_Other ":") (toSexp)} {(DQ (${ VSub_Name lambda))})
      terminator: <Op_Semi ";">
    )
    (C {(assert) (Lit_Other ":") (Lit_Other ":") (equals)} {(DQ ("(lambda () (+ 1 2) (+ 2 3))"))} 
      {(DQ (${ VSub_Name RESULT))} {(DQ ("(lambda () (+ 1 2) (+ 2 3))"))}
    )
    (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: [1028 1032]
                        )
                      } {(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 1054]
        )
      ]
      spids: [-1 1063]
    )
  ]
)