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Beoran 2f5cbd7491 Ponder design of fields more. 2 years ago
cmd 133c77fb0a Adding selectors but they don't work correctly yet. 2 years ago
test b19c0c32ae A few things work better now 2 years ago
LICENSE 534d46d7c8 Add MIT LICENSE. 2 years ago
README.md f17e62d27c Try different classes of operators. 2 years ago
alias.go 1a81159c54 Support operators, finally, if in a slightly roundabout way. Also support aliasing. 2 years ago
ast.go 133c77fb0a Adding selectors but they don't work correctly yet. 2 years ago
ast_test.go 969734636f Improve the lexer and work on the parser. 3 years ago
block.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
bool.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
builtin.go 133c77fb0a Adding selectors but they don't work correctly yet. 2 years ago
callable.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
console.go 8bfea9bd95 Implement chain syntax that also allows operators. 2 years ago
cover.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
defined.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
design_muesli.muesli 2f5cbd7491 Ponder design of fields more. 2 years ago
doc.go 5ffa4a6725 Lexer is still flaky, considering switching to state machine based lexer. 3 years ago
door.go 57076218b6 Considering objects with fields. 2 years ago
empty.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
error.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
float.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
frame.go 8bfea9bd95 Implement chain syntax that also allows operators. 2 years ago
go.mod 5e6a17f72a Starting to become runnable. 2 years ago
go.sum 5e6a17f72a Starting to become runnable. 2 years ago
help.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
int.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
keyword.go 8bfea9bd95 Implement chain syntax that also allows operators. 2 years ago
lexer.go 133c77fb0a Adding selectors but they don't work correctly yet. 2 years ago
lexer_test.go 433b2c57d0 Parser starts to work correctly. 3 years ago
list.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
logger.go 8bfea9bd95 Implement chain syntax that also allows operators. 2 years ago
map.go 57076218b6 Considering objects with fields. 2 years ago
muesli.go 5ffa4a6725 Lexer is still flaky, considering switching to state machine based lexer. 3 years ago
object.go 57076218b6 Considering objects with fields. 2 years ago
parser.go 2f5cbd7491 Ponder design of fields more. 2 years ago
parser_test.go 8bfea9bd95 Implement chain syntax that also allows operators. 2 years ago
redispatch.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
scope.go 8bfea9bd95 Implement chain syntax that also allows operators. 2 years ago
signature.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
string.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
token.go 133c77fb0a Adding selectors but they don't work correctly yet. 2 years ago
type.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
value.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago
vm.go 133c77fb0a Adding selectors but they don't work correctly yet. 2 years ago
vm_test.go ad6c510461 WIP return or fail. 2 years ago
word.go 027d3a2f29 Signatures for all callables. Think about type system. 2 years ago

README.md

Muesli is a Multi Use Embeddable Scripting Language Implementation.

Introduction

Muesli is a scripting language implemented in Go, that has a simple command chain based TCL or shell like syntax but with rich semantics. Unlike TCL or shels, all muelsi values are typed, and many types are supported, not just string values. Additionaly, if so desired, every symbol used in the syntax can be replaced by a key word, leading to a native language programming feel.

Syntax

A Muesli program consists of blocks and chains, separated by newlines or periods. A chain consists of one or more commands, linked together by operators.

  • A muesli program consists of statements.
  • A statement is either a block, or a command chain terminated by a newline, or just an empty line .
  • A command chain consists of commands chained together with operators. A command chain is evaluated by looking up and calling the the first operator in the chain, which receives the first command and the rest of the chain as arguments.
  • There are tree kinds of operators: substitute operators, block operators, and shuffle operators.
  • Substitute operators begin with one of +-*/ and will receive their arguments as already evaluated substitutions.
  • Block operators begin with one of |&<> and will recieve their arguments as unevaluated blocks.
  • Shuffle operators begin with one of ,; are interpreted as commands and the first operand will be an evaluated block, but the second operand is passed as is. Examples: $door , open -> , $door open $door , key , drop -> , (, key $door) drop ls | grep "foo" | sort > fopen "foo" -> | ls grep "foo" is evaluated as: > | (| (ls) (grep "foo")) (sort)) fopen "foo"
  • A command may be a direct command, a substitution, or a literal value.
  • A direct command consists of a name followed by zero or more parameters. A direct command is evaluated as follows: the name is looked up in the VM and executed if found and callable, with the given parameters, and evaluates to the return value to the callable. An error is raised if the name of the direct command is not found.
  • A substitution starts with an open parenthesis, followed by a command chain, followed by a close parenthesis. a substitution followed by zero or more parameters. A substitution is evaluated as the return value of the command chain inside the parenthesis of the substitution.
  • A bracketed list [ elem1 elem2 ... ] is syntactic sugar for (list elem1 elem 2)
  • A dollar getter $varname is syntactic sugar for (get varname)
  • A equals setter =varname value is syntactic sugar for (set varname value)
  • Therefore, parenthesis, lists, getters and setters are allowed anywhere, also in the beginning of the command with substitution semantics.
  • A literal value evaluates to itself.
  • A name also evaluates to itself when it is a parameter, but if it is at the beginning of a direct command, the name is looked up in the VM and called in stead if found, or an error is raised if not found.

Blocks consist of chains grouped together in blocks between braces {}. The commands in a block are not executed immediately but stored.

A single chain can be placed in parenthesis (), where the return value of the chain will be subsituted. Lists are formed by placing their contents between brackets [].

Every command has a return value, which can be of any type, and not just a number like in most shells. Furthermore commands have input and output, which default to stdin and stdout, but can be redirected or reconfigured.

There are three types of commands, namely direct commands, substitutions, and literal commands. A direct command starts with a name, and is followed by any number of parameters. Parameters may be which may be blocks, parenthesis, lists, names or literals, or values. An indirect command starts with a substitution followed by parameters. A literal command is simply a numeric, string, boolean or nil literal that evaluates to itself.

The language itself has no control statements, such as if, or for, these are implemented as commands in stead.

Muesly supports several kinds of values, namely:

  • Integers
  • Floats
  • Strings between "double quotes"
  • The booleans !true and !false
  • The nil value !nil
  • Words, which are simple runs of alphanumercial characters starting with a lower case lettter, such as foo
  • Types which are runs of alphanumerical characters starting with an upper case letter, such as Foo.