-: / /MOD SWAP DROP ;
-: MOD /MOD DROP ;
-
-: '\n' 10 ;
-: BL 32 ;
-
-: CR '\n' emit ;
-: SPACE BL emit ;
-
-: NEGATE 0 swap - ;
-
-: TRUE -1 ;
-: FALSE 0 ;
-: NOT 0= ;
-
-: LITERAL IMMEDIATE ' LIT , , ;
-
-: ':'
- [
- CHAR :
- ]
- LITERAL
-;
-
-: ';' [ CHAR ; ] LITERAL ;
-: '(' [ CHAR ( ] LITERAL ;
-: ')' [ CHAR ) ] LITERAL ;
-: '"' [ CHAR " ] LITERAL ;
-: 'A' [ CHAR A ] LITERAL ;
-: '0' [ CHAR 0 ] LITERAL ;
-: '-' [ CHAR - ] LITERAL ;
-: '.' [ CHAR . ] LITERAL ;
-
-\ While compiling, '[COMPILE] word' compiles 'word' if it would otherwise be IMMEDIATE.
-: [COMPILE] IMMEDIATE
- WORD \ get the next word
- FIND \ find it in the dictionary
- >CFA \ get its codeword
- , \ and compile that
-;
-
-\ RECURSE makes a recursive call to the current word that is being compiled.
-\
-\ Normally while a word is being compiled, it is marked HIDDEN so that references to the
-\ same word within are calls to the previous definition of the word. However we still have
-\ access to the word which we are currently compiling through the LATEST pointer so we
-\ can use that to compile a recursive call.
-: RECURSE IMMEDIATE
- LATEST @ \ LATEST points to the word being compiled at the moment
- >CFA \ get the codeword
- , \ compile it
-;
-
-\ CONTROL STRUCTURES ----------------------------------------------------------------------
-\
-\ So far we have defined only very simple definitions. Before we can go further, we really need to
-\ make some control structures, like IF ... THEN and loops. Luckily we can define arbitrary control
-\ structures directly in FORTH.
-\
-\ Please note that the control structures as I have defined them here will only work inside compiled
-\ words. If you try to type in expressions using IF, etc. in immediate mode, then they won't work.
-\ Making these work in immediate mode is left as an exercise for the reader.
-
-\ condition IF true-part THEN rest
-\ -- compiles to: --> condition 0BRANCH OFFSET true-part rest
-\ where OFFSET is the offset of 'rest'
-\ condition IF true-part ELSE false-part THEN
-\ -- compiles to: --> condition 0BRANCH OFFSET true-part BRANCH OFFSET2 false-part rest
-\ where OFFSET if the offset of false-part and OFFSET2 is the offset of rest
-
-\ IF is an IMMEDIATE word which compiles 0BRANCH followed by a dummy offset, and places
-\ the address of the 0BRANCH on the stack. Later when we see THEN, we pop that address
-\ off the stack, calculate the offset, and back-fill the offset.
-: IF IMMEDIATE
- ' 0BRANCH , \ compile 0BRANCH
- HERE @ \ save location of the offset on the stack
- 0 , \ compile a dummy offset
-;
-
-: THEN IMMEDIATE
- DUP
- HERE @ SWAP - \ calculate the offset from the address saved on the stack
- SWAP ! \ store the offset in the back-filled location
-;
-
-: ELSE IMMEDIATE
- ' BRANCH , \ definite branch to just over the false-part
- HERE @ \ save location of the offset on the stack
- 0 , \ compile a dummy offset
- SWAP \ now back-fill the original (IF) offset
- DUP \ same as for THEN word above
- HERE @ SWAP -
- SWAP !
-;
-
-\ BEGIN loop-part condition UNTIL
-\ -- compiles to: --> loop-part condition 0BRANCH OFFSET
-\ where OFFSET points back to the loop-part
-\ This is like do { loop-part } while (condition) in the C language
-: BEGIN IMMEDIATE
- HERE @ \ save location on the stack
-;
-
-: UNTIL IMMEDIATE
- ' 0BRANCH , \ compile 0BRANCH
- HERE @ - \ calculate the offset from the address saved on the stack
- , \ compile the offset here
-;
-
-\ BEGIN loop-part AGAIN
-\ -- compiles to: --> loop-part BRANCH OFFSET
-\ where OFFSET points back to the loop-part
-\ In other words, an infinite loop which can only be returned from with EXIT
-: AGAIN IMMEDIATE
- ' BRANCH , \ compile BRANCH
- HERE @ - \ calculate the offset back
- , \ compile the offset here
-;
-
-\ BEGIN condition WHILE loop-part REPEAT
-\ -- compiles to: --> condition 0BRANCH OFFSET2 loop-part BRANCH OFFSET
-\ where OFFSET points back to condition (the beginning) and OFFSET2 points to after the whole piece of code
-\ So this is like a while (condition) { loop-part } loop in the C language
-: WHILE IMMEDIATE
- ' 0BRANCH , \ compile 0BRANCH
- HERE @ \ save location of the offset2 on the stack
- 0 , \ compile a dummy offset2
-;
-
-: REPEAT IMMEDIATE
- ' BRANCH , \ compile BRANCH
- SWAP \ get the original offset (from BEGIN)
- HERE @ - , \ and compile it after BRANCH
- DUP
- HERE @ SWAP - \ calculate the offset2
- SWAP ! \ and back-fill it in the original location
-;
-
-\ UNLESS is the same as IF but the test is reversed.
-\
-\ Note the use of [COMPILE]: Since IF is IMMEDIATE we don't want it to be executed while UNLESS
-\ is compiling, but while UNLESS is running (which happens to be when whatever word using UNLESS is
-\ being compiled -- whew!). So we use [COMPILE] to reverse the effect of marking IF as immediate.
-\ This trick is generally used when we want to write our own control words without having to
-\ implement them all in terms of the primitives 0BRANCH and BRANCH, but instead reusing simpler
-\ control words like (in this instance) IF.
-: UNLESS IMMEDIATE
- ' NOT , \ compile NOT (to reverse the test)
- [COMPILE] IF \ continue by calling the normal IF
-;
-
-\ COMMENTS ----------------------------------------------------------------------
-\
-\ FORTH allows ( ... ) as comments within function definitions. This works by having an IMMEDIATE
-\ word called ( which just drops input characters until it hits the corresponding ).
-: ( IMMEDIATE
- 1 \ allowed nested parens by keeping track of depth
- BEGIN
- KEY \ read next character
- DUP '(' = IF \ open paren?
- DROP \ drop the open paren
- 1+ \ depth increases
- ELSE
- ')' = IF \ close paren?
- 1- \ depth decreases
- THEN
- THEN
- DUP 0= UNTIL \ continue until we reach matching close paren, depth 0
- DROP \ drop the depth counter
-;
-
-(
- From now on we can use ( ... ) for comments.
-
- STACK NOTATION ----------------------------------------------------------------------
-
- In FORTH style we can also use ( ... -- ... ) to show the effects that a word has on the
- parameter stack. For example:
-
- ( n -- ) means that the word consumes an integer (n) from the parameter stack.
- ( b a -- c ) means that the word uses two integers (a and b, where a is at the top of stack)
- and returns a single integer (c).
- ( -- ) means the word has no effect on the stack
-)
-
-( Some more complicated stack examples, showing the stack notation. )
-: NIP ( x y -- y ) SWAP DROP ;
-: TUCK ( x y -- y x y ) DUP ROT ;
-: PICK ( x_u ... x_1 x_0 u -- x_u ... x_1 x_0 x_u )
- 1+ ( add one because of 'u' on the stack )
- PSP@ SWAP - ( add to the stack pointer )
- @ ( and fetch )
-;
-
-( With the looping constructs, we can now write SPACES, which writes n spaces to stdout. )
-: SPACES ( n -- )
- BEGIN
- DUP 0> ( while n > 0 )
- WHILE
- SPACE ( print a space )
- 1- ( until we count down to 0 )
- REPEAT
- DROP
-;
-
-( Standard words for manipulating BASE. )
-: DECIMAL ( -- ) 10 BASE ! ;
-: HEX ( -- ) 16 BASE ! ;
-
-(
- PRINTING NUMBERS ----------------------------------------------------------------------
-
- The standard FORTH word . (DOT) is very important. It takes the number at the top
- of the stack and prints it out. However first I'm going to implement some lower-level
- FORTH words:
-
- U.R ( u width -- ) which prints an unsigned number, padded to a certain width
- U. ( u -- ) which prints an unsigned number
- .R ( n width -- ) which prints a signed number, padded to a certain width.
-
- For example:
- -123 6 .R
- will print out these characters:
- <space> <space> - 1 2 3
-
- In other words, the number padded left to a certain number of characters.
-
- The full number is printed even if it is wider than width, and this is what allows us to
- define the ordinary functions U. and . (we just set width to zero knowing that the full
- number will be printed anyway).
-
- Another wrinkle of . and friends is that they obey the current base in the variable BASE.
- BASE can be anything in the range 2 to 36.
-
- While we're defining . &c we can also define .S which is a useful debugging tool. This
- word prints the current stack (non-destructively) from top to bottom.
-)
-
-( This is the underlying recursive definition of U. )
-: U. ( u -- )
- BASE @ /MOD ( width rem quot )
- ?DUP IF ( if quotient <> 0 then )
- RECURSE ( print the quotient )
- THEN
-
- ( print the remainder )
- DUP 10 < IF
- '0' ( decimal digits 0..9 )
- ELSE
- 10 - ( hex and beyond digits A..Z )
- 'A'
- THEN
- +
- EMIT
-;
-
-
+: \ IMMEDIATE
+ #IB @ >IN !
+; \ We can now comment!
+
+\ Compile core definitions
+\ (These files must be compiled in order!)
+
+include lib_1_basic.4th
+include lib_2_control.4th
+include lib_3_input.4th
+include lib_4_comments.4th
+include lib_5_printnum.4th
+include lib_6_strings.4th
+include lib_7_variables.4th
+include lib_8_vocab.4th
+include lib_9_decompiler.4th
+include lib_10_misc.4th
+include lib_11_extensions.4th
+
+: LICENSE
+ CR
+ ." This program is free software: you can redistribute it and/or modify" CR
+ ." it under the terms of the GNU General Public License as published by" CR
+ ." the Free Software Foundation, either version 3 of the License, or" CR
+ ." (at your option) any later version." CR
+ ." " CR
+ ." This program is distributed in the hope that it will be useful," CR
+ ." but WITHOUT ANY WARRANTY; without even the implied warranty of" CR
+ ." MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the" CR
+ ." GNU General Public License for more details." CR
+ ." " CR
+ ." You should have received a copy of the GNU General Public License" CR
+ ." along with this program. If not, see http://www.gnu.org/licenses/." CR
+;
+
+: WELCOME
+ SKIP-WELCOME @ INVERT IF
+ ." Welcome to forth.jl!" CR CR
+
+ ." Copyright (C) 2016 Tim Vaughan" CR
+ ." This program comes with ABSOLUTELY NO WARRANY; for details type 'license'" CR
+ ." Type 'bye' or press Ctrl+D to exit." CR CR
+ THEN
+;
+welcome
The Lambda Lab / projects / forth.jl.git / blobdiff