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Keywords.dm
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Keywords.dm
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/*
* File: Keywords
*/
#define KW_FAIL 0 //Fatal error; stop parsing entire script.
#define KW_PASS 1 //OK
#define KW_ERR 2 //Non-fatal error, keyword couldn't be handled properly. Ignore keyword but continue on.
#define KW_WARN 3 //Warning
/*
* n_Keyword
* Represents a special statement in the code triggered by a keyword.
*/
/datum/n_Keyword
///Boolean if the keyword is in an expression (e.g. the new keyword in many languages).
var/inline
/datum/n_Keyword/New(inline = 0)
src.inline = inline
return ..()
/*
* Parse
* Called when the parser finds a keyword in the code.
*
* Arguments:
* parser - The parser that created this object.
* You can use the parameter to manipulate the parser in order to add statements and blocks to its AST.
*/
/datum/n_Keyword/proc/Parse(datum/n_Parser/parser)
/*
* nS_Keyword
* A keyword in n_Script. By default these include return, if, else, while, and def. To enable or disable a keyword, change the
* <nS_Options.keywords> list.
*
* Behavior:
* When a parser is expecting a new statement, and a keyword listed in <nS_Options.keywords> is found, it will call the keyword's
* <n_Keyword.Parse()> proc.
*/
/datum/n_Keyword/nS_Keyword
/datum/n_Keyword/nS_Keyword/New(inline = 0)
if(inline)
qdel(src)
/datum/n_Keyword/nS_Keyword/kwReturn
/datum/n_Keyword/nS_Keyword/kwReturn/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
if(istype(parser.curBlock, /datum/node/BlockDefinition/GlobalBlock)) // Exit out of the program by setting the tokens list size to the same as index.
parser.tokens.len = parser.index
return
var/datum/node/statement/ReturnStatement/stmt = new(parser.curToken)
parser.NextToken() //skip 'return' token
stmt.value=parser.ParseExpression()
parser.curBlock.statements += stmt
/datum/n_Keyword/nS_Keyword/kwIf
/datum/n_Keyword/nS_Keyword/kwIf/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
var/datum/node/statement/IfStatement/stmt = new(parser.curToken)
parser.NextToken() //skip 'if' token
stmt.cond=parser.ParseParenExpression()
if(!parser.CheckToken(")", /datum/token/symbol))
return KW_FAIL
if(!parser.CheckToken("{", /datum/token/symbol, skip=0)) //datum/token needs to be preserved for parse loop, so skip=0
return KW_ERR
parser.curBlock.statements += stmt
stmt.block=new
parser.AddBlock(stmt.block)
/datum/n_Keyword/nS_Keyword/kwElseIf
/datum/n_Keyword/nS_Keyword/kwElseIf/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
var/list/L = parser.curBlock.statements
var/datum/node/statement/IfStatement/ifstmt
if(L && L.len)
ifstmt = L[L.len] //Get the last statement in the current block
if(!ifstmt || !istype(ifstmt) || ifstmt.else_if)
parser.errors += new /datum/scriptError/ExpectedToken("if statement", parser.curToken)
return KW_FAIL
var/datum/node/statement/IfStatement/ElseIf/stmt = new(parser.curToken)
parser.NextToken() //skip 'if' token
stmt.cond = parser.ParseParenExpression()
if(!parser.CheckToken(")", /datum/token/symbol))
return KW_FAIL
if(!parser.CheckToken("{", /datum/token/symbol, skip = FALSE)) //datum/token needs to be preserved for parse loop, so skip=0
return KW_ERR
parser.curBlock.statements += stmt
stmt.block = new
ifstmt.else_if = stmt
parser.AddBlock(stmt.block)
/datum/n_Keyword/nS_Keyword/kwElse
/datum/n_Keyword/nS_Keyword/kwElse/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
var/list/L = parser.curBlock.statements
var/datum/node/statement/IfStatement/stmt
if(L&&L.len) stmt=L[L.len] //Get the last statement in the current block
if(!stmt || !istype(stmt) || stmt.else_block) //Ensure that it is an if statement
parser.errors += new /datum/scriptError/ExpectedToken("if statement",parser.curToken)
return KW_FAIL
parser.NextToken() //skip 'else' token
if(!parser.CheckToken("{", /datum/token/symbol, skip=0))
return KW_ERR
stmt.else_block=new()
parser.AddBlock(stmt.else_block)
/datum/n_Keyword/nS_Keyword/kwWhile
/datum/n_Keyword/nS_Keyword/kwWhile/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
var/datum/node/statement/WhileLoop/stmt = new(parser.curToken)
parser.NextToken() //skip 'while' token
stmt.cond=parser.ParseParenExpression()
if(!parser.CheckToken(")", /datum/token/symbol))
return KW_FAIL
if(!parser.CheckToken("{", /datum/token/symbol, skip=0))
return KW_ERR
parser.curBlock.statements += stmt
stmt.block = new
parser.AddBlock(stmt.block)
/datum/n_Keyword/nS_Keyword/kwFor
/datum/n_Keyword/nS_Keyword/kwFor/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
var/datum/node/statement/ForLoop/stmt = new(parser.curToken)
parser.NextToken()
if(!parser.CheckToken("(", /datum/token/symbol))
return KW_FAIL
stmt.init = parser.ParseExpression()
if(!parser.CheckToken(";", /datum/token/end))
return KW_FAIL
stmt.test = parser.ParseExpression()
if(!parser.CheckToken(";", /datum/token/end))
return KW_FAIL
stmt.increment = parser.ParseExpression(list(")"))
if(!parser.CheckToken(")", /datum/token/symbol))
return KW_FAIL
if(!parser.CheckToken("{", /datum/token/symbol, skip=0))
return KW_ERR
parser.curBlock.statements += stmt
stmt.block = new
parser.AddBlock(stmt.block)
/datum/n_Keyword/nS_Keyword/kwBreak
/datum/n_Keyword/nS_Keyword/kwBreak/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
if(istype(parser.curBlock, /datum/node/BlockDefinition/GlobalBlock))
parser.errors += new /datum/scriptError/BadToken(parser.curToken)
. = KW_WARN
var/datum/node/statement/BreakStatement/stmt = new(parser.curToken)
parser.NextToken() //skip 'break' token
parser.curBlock.statements += stmt
/datum/n_Keyword/nS_Keyword/kwContinue
/datum/n_Keyword/nS_Keyword/kwContinue/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
if(istype(parser.curBlock, /datum/node/BlockDefinition/GlobalBlock))
parser.errors += new /datum/scriptError/BadToken(parser.curToken)
. = KW_WARN
var/datum/node/statement/ContinueStatement/stmt = new(parser.curToken)
parser.NextToken() //skip 'break' token
parser.curBlock.statements += stmt
/datum/n_Keyword/nS_Keyword/kwDef
/datum/n_Keyword/nS_Keyword/kwDef/Parse(datum/n_Parser/nS_Parser/parser)
. = KW_PASS
var/datum/node/statement/FunctionDefinition/def = new(parser.curToken)
parser.NextToken() //skip 'def' token
if(!parser.options.IsValidID(parser.curToken.value))
parser.errors += new /datum/scriptError/InvalidID(parser.curToken)
return KW_FAIL
def.func_name=parser.curToken.value
parser.NextToken()
if(!parser.CheckToken("(", /datum/token/symbol))
return KW_FAIL
while(TRUE) //for now parameters can be separated by whitespace - they don't need a comma in between
if(istype(parser.curToken, /datum/token/symbol))
switch(parser.curToken.value)
if(",")
parser.NextToken()
if(")")
break
else
parser.errors += new /datum/scriptError/BadToken(parser.curToken)
return KW_ERR
else if(istype(parser.curToken, /datum/token/word))
def.parameters+=parser.curToken.value
parser.NextToken()
else
parser.errors += new /datum/scriptError/InvalidID(parser.curToken)
return KW_ERR
if(!parser.CheckToken(")", /datum/token/symbol))
return KW_FAIL
if(istype(parser.curToken, /datum/token/end)) //Function prototype
parser.curBlock.statements+=def
else if(parser.curToken.value == "{" && istype(parser.curToken, /datum/token/symbol))
def.block = new
parser.curBlock.statements.Insert(1, def) // insert into the beginning so that all functions are defined first
parser.curBlock.functions[def.func_name]=def
parser.AddBlock(def.block)
else
parser.errors += new /datum/scriptError/BadToken(parser.curToken)
return KW_FAIL
#undef KW_FAIL
#undef KW_PASS
#undef KW_ERR
#undef KW_WARN